The first practice for the Arizona Cardinals in pads — the one where the hitting begins — seemed for an instant to be the final practice that would matter.
Safety Tyrann Mathieu knocked a blocker into quarterback Carson Palmer, who went down in a heap, momentarily stunning players, coaches, and fans.
Palmer, coming back from a November 7 knee injury that ended his 2014 season, turned out to be all right.
But the incident underscored the fragility of the Cardinals' shot at a Super Bowl run. The team had the best record in the National Football League when Palmer went down last season, and though the team didn't tank, they had no chance of winning a playoff game by season's end.
Mathieu began checking daily on Palmer's well-being, the quarterback says.
"I think he was more scared than I was," Palmer says.
The veteran had been through this before.
In Cincinnati, he was hit low early in the Bengals' playoff opener following the 2005 season (in which he led the team to an 11-5 record, its first winning season since 1990) and had to undergo an extensive knee surgery.
Palmer bounced back quickly. He started the next season and ended up having a banner year, throwing 28 touchdowns with 13 interceptions, which added up to a stellar 93.9 quarterback rating and a Pro Bowl selection.
Like the one he suffered last fall, the knee injury he sustained with Cincinnati was extremely serious.
"Two completely different injuries," he says. "On one, somebody came down and hit me low. It was a collision injury. On this [last] one, there was no collision — it just popped.
"There were mental hurdles the first time, especially the way it happened. I remember coming back, especially at the beginning of the  season and . . . maybe not stepping into a throw [to protect] the knee. I don't feel that way now."
At 35, he says, "I feel great. A good reason for that is that I'm too old to do what I used to do. When I was in Cincinnati, we had a golf course literally three minutes away. Between meetings, we would go play . . . and there was a basketball court."
Now, when he's not practicing, he's at home.
"I was an idiot [with the Bengals], doing way too much between practices. [Now] my feet are up, and I'm resting and studying. I feel better."
It looks that way.
Palmer was the star of training camp.
The consensus among experts is that he was as sharp in the preseason as any Cardinals quarterback since the team's move from St. Louis in 1988, including Kurt Warner during the Cardinals' 2008 Super Bowl year.
His most spectacular throw at training camp was a bomb to speedster John "Smokey" Brown, a receiver with whom Palmer has a special connection (he tutored Brown before the receiver's rookie season). Coach Bruce Arians says the pass, which was thrown early in camp, traveled 65 yards. It hit Brown in stride, and the receiver finished the play with a spectacular somersault in the end zone.
Palmer estimates that he made the pass after throwing at least 90 balls in the practice.
"When you get those opportunities, you've got to make them," Palmer says. "It felt good to see Smokey get under that ball."
After massive rehabilitation work over the past several months, Palmer appears stronger than in his two previous seasons with the Cardinals. Arians praises his quarterback's meticulous preparation:
"The game is evolving and changing every day. We're throwing blitzes at him every day. He works as hard at his craft as any guy I know."
While an assistant coach in Pittsburgh, Arians' Steelers played Palmer and the Bengals twice a season:
"I knew he was tough because we tried to kill him in Pittsburgh every time we played him. He always answered the bell. In the fourth quarter, he'd still be standing. But I didn't know how big a gym rat he was until I started working with him."
Left guard Mike Iupati, who got his first close look at Palmer after signing as a free agent from the rival San Francisco 49ers, calls him "an awesome, phenomenal" quarterback.
But he says there's a big difference in blocking for him as opposed to the 49ers' crafty Colin Kaepernick.
"When the pocket collapsed with the Niners, [Kaepernick] could run the ball," Iupati says. With the slower, more traditional pocket-passing Palmer, "you have to do everything to protect him."
Star receiver Larry Fitzgerald believes this will be Palmer's greatest season:
"He's healthy. He's confident. He's got a lot of talented players around him . . . When you couple that with confidence and his experience, it's a dangerous combination."
Most importantly, Arians says, his starting quarterback is improving in the twilight of his career:
"Every day, the arrow is going up — he's extremely efficient right now."
That there is more optimism than ever about the Cardinals was proved by the record 23,000 estimated to have attended their August 8 scrimmage in Glendale.
The principal reason seems to be that — for the first time since the Cardinals moved to Arizona in 1988 — there are few public jitters about the competence of either the head coach or the general manager.
Both Bruce Arians, named the NFL's coach of the year twice in the past three years, and general manager Steve Keim are entering their third seasons in charge.
Arians, proof that the best assistant coaches sometimes labor in the shadows for most or all of their careers, is particularly admired.
Bypassed many times as NFL executives hired previously fired or up-and-coming, young coaches, he took over the Indianapolis Colts in 2012 in an emergency situation (coach Chuck Pagano's leukemia diagnosis). Following that season, Arians was named coach of the year for the first time.
When Pagano returned to good health, Cardinals owner Michael Bidwill was the quickest to recognize that the then-60-year-old Arians clearly was ready for a head coaching job. The coach-of-the-year nod made it apparent that Arians wouldn't return to his job as offensive coordinator for Indianapolis.
Arians' 21-12 record in his first two seasons is stunning, especially given that he inherited a dysfunctional system featuring alternating quarterbacks, a porous offensive line, and terrible production from largely no-name or over-the-hill running backs.
Before his arrival, the 2012 Cardinals had lost 11 of their last 12 games, including one in Atlanta in which Arizona's competent defense forced six turnovers. Losing under such circumstances is all but unprecedented.
Keim came up through the ranks of Cardinals scouts. His was an influential voice in drafting players in the mistake-prone era of coach Ken Whisenhunt and GM Rod Graves.
So he had baggage when he took over as GM.
But so far he has been a savant at last-minute, bargain acquisitions. Examples include linebackers John Abraham in 2013 and Larry Foote last season.
Some of his high draft picks have yet to flourish, but there have been big successes.
The most impressive of his acquisitions from the college crop is gifted safety Mathieu, the Cardinals' third-round pick in the 2013 draft, the first run by Keim.
There are cautionary tales, though. A key injury on the offensive line has set the Cardinals back this year, as has a foolish offseason mistake involving an important offensive lineman.
If Arians and Keim can plug such holes, the team has a chance to make history.
The Cardinals are the oldest franchise in pro football, with roots dating to 1898 in Chicago, but they never have made the league playoffs three years in a row and haven't won a title since 1947. They and the Chicago Bears are the only franchises still around from the birth of the league in 1920.
If they were to win the next Super Bowl, it would be the football equivalent of the Chicago Cubs winning the World Series.
Starting Sunday, September 13, when the Cardinals open at home against the New Orleans Saints, fans will begin to get a sense of whether the team can make a championship run.
It will help the Cardinals' chances if they make it until early October without a loss. They have three early games at home, and the first four are against teams that didn't make the playoffs last season. Their sole road game is against the lowly Bears.
It gets harder after that.
The Cardinals' closing three games are against three of the top contenders in the National Football Conference: On December 20, they play the Philadelphia Eagles on the road, and after Christmas, they play home games against the Green Bay Packers and the Seattle Seahawks, two preseason picks by Las Vegas bookies to win the Super Bowl. The Packers narrowly missed going to the big game last season, and the Seahawks have been there each of the past two years, winning it following the 2013 season.
That the Cardinals play in the same NFC West Division as Seattle makes their journey to a title all the more perilous, since they play the 'Hawks twice every season.
But Arians' Cardinals are one of two teams to have beaten Seattle at home — where fans who scream themselves hoarse are known as "The 12th Man" — in the past two seasons.
Bruce Arians challenged defensive lineman Calais Campbell in the offseason: Good isn't good enough.
Campbell is one of three Cardinals remaining from the 2008-09 Super Bowl season (Fitzgerald and center Lyle Sendlein are the others).
That season, Campbell was a backup and a special-teams player. The sight of the 6-8 300-pounder racing full speed downfield after kicks truly was frightening.
Campbell gradually has matured into a powerful defensive end.
Last season, for the first time, he made the Pro Bowl. And now, he's cracked the NFL players' annual survey naming their top 100 players at 99.
But Arians wants more, saying he didn't always see intense, play-making energy from Campbell last season.
"He can be one of the best in the league playing all the time at his best," the coach says. "With his length and his explosiveness, he should be unblockable."
All of which started a debate at training camp.
Campbell is as friendly as he is huge. For reporters, he is the favorite interview subject on the team. He helps host the Cardinals' weekly radio show, and during off-field encounters, he doesn't seem to have a mean bone in his body.
He's the least likely guy on the team to get into trouble. For example, during the Cardinals' weeklong stay on the East Coast during his 2008 rookie season (the team played in Washington and New York on consecutive Sundays), Campbell was spotted late in the evening after the Cards' loss to the Redskins.
But he wasn't partying at a loud Georgetown bar; he and a couple of friends were exploring a Georgetown home listed as the oldest in the nation's capital, a historic landmark open late for tourists.
The question became: Is Campbell too nice to play nasty? Did Cardinals coaches need to figure out a way to make him meaner?
"This question has been asked about certain players for about 50 years in [football] coaching," Arians says.
Campbell is entering his eighth NFL season. His personality isn't going to change.
Arians believes that Campbell doesn't need to be an off-the-field brawler to become dominant.
Looking across the locker room at soft-spoken Tyrann Mathieu, who hits as hard, tackles as well, and generally plays as aggressively as anybody in the league, it's evident that nice guys can play tough.
"When I'm in the locker room, I probably don't say two or three words," Mathieu says. "Once I put my helmet on, I try to become a different person. I try to raise my energy level so teammates can feed off me."
Arians decided that the way to motivate Campbell was to challenge him to be the best at his position.
Campbell has more swagger since making the Pro Bowl, Arians says: "And he should. He's still working on his craft and getting better every day."
In the final analysis, Arians says: "He's mean enough [on the field]."
Defensive end Frostee Rucker agrees:
"He's a great guy," he says of Campbell, "but he's all business when it comes to football.
"I used to have the same stigma. I smiled too much. But [that this was a sign of weakness as a player] was just the perception of people who don't know who you truly are."
Rucker believes Campbell will have a big year.
"He's not talking about being the best, but he's putting in the work to do it. It's going to show. He's done some spectacular stuff in practice. He's honing in on trying to be technically solid. And he's so physically gifted that he can make plays that a normal person can't make."
To make the jump to playing dominantly, Campbell put himself through grueling workouts earlier this summer under the guidance of Jay Glazer, best known as Fox Sports' "NFL Insider."
Glazer's other job is training football players, mixed martial arts fighters, and other athletes in a Los Angeles gym. Campbell moved to L.A. for about a month to work with Glazer and a team of coaches. He and other players in the program ran, lifted weights, performed agility drills, and worked extensively on hand-fighting techniques.
To work on leverage, they engaged in Greco-Roman wrestling, in which combatants cannot grab opponents below the waist.
"You've got to play with leverage," Glazer says. "When you stand straight up, you've lost the leverage game. The low man always wins . . . I'm a 5-foot-7 Jewish guy, [and] they can't move me."
While much of the training involved skills that translate directly to football, there is an important psychological component, Glazer says:
"The NFL can do and say as much as it wants about taking away the word 'violence.' It's still a game of violence. That guy across from you is trying to knock your head off. You break his will before he breaks yours.
"We find your breaking point," he says of his workouts with athletes. "We move your breaking point farther than you ever thought it could go. As a result, when you're out there playing football, you figure, 'Well, I'm not tired. That stuff I did with Glazer. Now that was exhausting.'"
The NFL, Glazer says, is a series of one-on-one fights.
"Our job is to teach you how to win these fights. It's basically a 12-second round with a one-minute break."
Campbell's workouts sometimes went for 10 arduous minutes before a break, Glazer says.
Glazer considers Campbell an "A" student.
"[Physically], he worked his butt off. He improved a ton."'
Is he too nice to achieve greatness at his position?
"You can skew that line," Glazer says. You can be the sweetest human being off the field, and you can be the nastiest, meanest, most violent S.O.B. when you're on it.
"I call it finding that dog in you and letting it out."
Says Campbell, "This is the best shape I've been in for a long time. I have been doing a lot better with my hands — hand speed, hand violence.
"I don't have to make every tackle [to be dominant every day]. I don't have to make every sack. I just have to be disruptive."
As for Arians' challenge, he says, "The best coaches are the ones who can get the best out of their players.
"Obviously, he sees more in me. He's motivated me to want to produce more . . . I know that sometimes you can be content with being good. But there's a different level to being the best consistently. It's a constant grind."
Patrick Peterson is as accomplished a football player at age 25 as anybody in the sport's history.
Peterson has made the Pro Bowl in all four of his NFL seasons and twice was named first-team All Pro.
And he's getting paid to be a superstar, with a $70 million contract extension that runs from 2016 through 2020. It's the most money ever paid to a cornerback.
Peterson recently was pegged as the league's 19th-best player in the aforementioned poll of players.
Yet his production failed to match his reputation last season, when — except for a few brilliant games — he turned in pedestrian performances.
There was a reason for the downturn: Peterson developed diabetes, which made him sluggish and made his weight difficult to control. Peterson says the condition now is under control.
In fact, he reported to training camp appearing extremely fit.
He and his pal, Mathieu, are keys to a defensive secondary that may be the NFL's best.
That neither has even entered the prime of his career is a tantalizing prospect for Cardinals coaches.
"He's probably got a year or so before he reaches his prime," former Cardinals safety Adrian Wilson says of Peterson. "But time is ticking. I think he realizes the time is now for him and for this team."
Wilson, who will go into the Cardinals' Ring of Honor this season, and Peterson were teammates in 2011 and '12.
What stood out about Peterson was his maturity, Wilson says: "He was very willing to learn. He wanted to be great. One of the things I liked most was that he wasn't afraid of hard work. He is super-talented, but the work he put in is what separated him from a lot of guys."
Describing himself as Peterson's "worst critic," Wilson notes that "consistency always will be an issue" because Peterson is charged with covering opponents' best receivers every week.
"It takes a lot of focus," Wilson says. "They design things to beat corners every Sunday. He just has to constantly improve."
Peterson says he enters this season "with an extra chip on my shoulder" because of the way he played last year.
"It was disappointing," he says. "Although I still made the Pro Bowl, I just feel, for myself, I didn't play to the best of my ability."
He claims he won't make excuses.
But, he says, "Physically, I wasn't able to put myself in a position to make plays. I was a step behind . . . That was due to my weight, to sluggish movement. Now, all that is behind me. That won't happen again."
It helps that Peterson has a fellow star in the defensive backfield in safety Mathieu, Peterson's teammate at Louisiana State University in 2010.
Coming out of college, former Heisman Trophy candidate Mathieu was infamous for smoking marijuana and getting kicked off his team at a football-crazy university. He was considered by many league executives to be too immature to make it in the NFL.
The Cardinals took a chance on him as a third-round pick in 2013, in part because he would have an excellent support system led by Peterson.
Sure enough, he has turned in stellar performances, and there has been no off-the-field drama; experts consider him one of the Cardinals' best players, and he's respected by teammates and coaches.
Many say he was the Cardinals' top defensive player at training camp.
"I'm a true believer in second chances," Arians says.
"After having met Ty during the draft process, I knew how passionate he was. And how much he regretted the mistakes he had made and admitted to them. He had a plan how to fix things.
"I'm not one of those guys who . . . throws a guy to the wolves because of public perception that he's a bad guy.
"I was one of those 'bad guys' [as a young man]," Arians says. "I think I did okay."
Mathieu intercepted a pass almost every day during training camp, then he intercepted a pass in the fifth defensive play of the Cardinals' exhibition game against the Kansas City Chiefs.
"That's the guy I'm used to seeing," Peterson says. "We know that he has the ability. It's all about staying healthy and being consistent. That's why the Cardinals drafted him. They know he's able to make those splash plays.
"He's all over the field. He's just a ball magnet. I think he'll help us in the long run if he's able to stay healthy and continues doing the things he's been doing to be a professional."
Peterson makes it clear that he's no longer Mathieu's babysitter.
"He understands what he has to do; he understands what we're looking for, the player we need him to be," Peterson says.
"I wish I had been able to play with him," Wilson says of Mathieu, who joined the team in 2013, a year after Wilson departed.
"He really gives the defense a ball-hawk dimension they haven't had for a while . . . He's probably more instinctive than anyone I've seen in a long, long time."
Wilson made big plays himself, but he points out: "I was freelancing a lot" and took chances. "[Mathieu] makes a lot of plays within the structure of the defense. That's huge when you have a guy who can do that."
Both former LSU stars have endured doubters, football insiders who said Mathieu wasn't disciplined enough to make it in the NFL and said Peterson wasn't good enough to deserve his big contract.
"We cannot wait to get on the field," Peterson says, "and show the world we are the real deal."
The NFL's six-week training camp and exhibition schedule can take a toll on a team.
Injuries pile up in franchise owners' scheme to make season-ticket holders pay full price for two home preseason games (20 percent of the total bill). The protracted exhibition schedule exists even though players spend weeks of the offseason training on their own, in non-contact practices and mini-camps. With a few exceptions, everyone is in shape to play before the beginning of camp.
So, almost predictably, the Cardinals lost players over the month and a half before the regular season.
Receiver Michael Floyd dislocated three fingers making a catch; he could be ready for the opener or maybe the second game at Chicago.
Left guard Mike Iupati then suffered a knee injury that could cost him a game or two, maybe several. He had signed a five-year deal worth up to $40 million. With him paired with left tackle Jared Veldheer, the Cardinals were supposed to be able to run roughshod on the left side of the field.
But the most aggravating problem involved another offensive lineman, and it had nothing to do with injury.
Right tackle Bobby Massie was arrested for driving under the influence late at night while sitting in his car at the Cardinals' Tempe training complex just before this year's Patriots-Seahawks Super Bowl in Glendale. Cops were alerted by a security guard who earlier had noticed an erratic driver.
Tackles are crucial to the success of a team's offense because they are charged primarily with protecting the quarterback, giving him time to make big plays — and Massie had become solid at the position last year.
Massie will be suspended for the first two games of the season.
Not only has the incident hurt the Cardinals because of the loss of a starter at a crucial position, but the arrest undoubtedly affected the Cardinals' approach to the draft.
Instead of using their first-round pick to acquire an exceptional running back (they desperately have needed help at the position for years), the team — wary of Massie's looming suspension — used the pick on offensive tackle D.J. Humphries, a star at the University of Florida.
Testament to the Cardinals' deficiency at running back is that the team's offense finished 31st in rushing last season, with just 81.8 yards per game.
Humphries got off got off to such a poor start in camp that Arians was infuriated.
"[Coaches have had to] put a knee in his ass every day," Arians says. "A foot wasn't going to do it."
Thus, Humphries was tagged with the nickname "Knee Deep."
Arians moaned at one point that Humphries "shows up once a week" at practice and that he had done little to prevent a quarterback sack in a preseason game against the San Diego Chargers.
Making this draft choice particularly damaging to the Cardinals' championship aspirations is that they were thought to be a leading candidate to land superstar running back Adrian Peterson in the offseason. Peterson, who had been suspended following a domestic-violence incident involving his child, eventually returned to the Minnesota Vikings.
If the Cardinals could have offered the Vikings their first-round pick — the one they used to acquire another offensive lineman — they might have had a chance at Peterson.
Instead of the struggling Humphries lining up in front of Palmer in an often vain attempt to protect the frequently injured linchpin of the Cardinals offense, Peterson might have lined up behind the quarterback and rushed for a thousand-plus-yard season. Peterson has done this in six of his eight NFL seasons.
GM Keim, however, may have fixed the situation — as much as it can be fixed — with his acquisitions of running backs Andre Ellington and rookie David Johnson, who got off to injury-marred starts in training camp.
Their injury histories had everything to do with Keim's signing veteran Chris Johnson, a former 2,000-yard runner, as insurance.
Though none is as good as Adrian Peterson, all three backs can catch as consistently as they can run.
Ellington, who missed much of 2014 with an ankle injury, offers speed and elusiveness. David Johnson adds power and quickness.
As for Chris Johnson, turning 30 this month, he's an able backup to Ellington. In the Cardinals' final preseason game with the Denver Broncos, he rushed for 45 yards, including an elusive 16-yard carry, and caught a 10-yard pass, in limited duty.
In the two earlier exhibition games against Kansas City and the Oakland Raiders, the team's liabilities on the offensive line surfaced. Without Iupati and Massie, Palmer either was running for cover or getting sacked repeatedly.
Despite this, the Cardinals' offense can be dynamic with a healthy Ellington and receivers John Brown and J.J. Nelson on the field.
The three are among the fastest offensive players in the NFL. The nicknames "Smoke" (for Brown, already known as Smokey) and "Fire" (for Nelson) emerged during training camp.
Brown, who believes he's in the best shape of his life after giving up fast food and soda, says, "I can run a deep ball, come back, run another deep ball, and I'm barely tired. I can run all day."
As for the Cardinals' defense, it took a big hit when nose tackle Corey Peters suffered a season-ending torn left Achilles tendon in practice. Peters had signed a three-year deal worth up to $9 million. He tore the same tendon in his right leg in late 2013 while playing for the Atlanta Falcons.
This leaves the position to unproven fourth-round draft pick Rodney Gunter.
Yet the Cardinals are solid to dominant overall on defense, despite the problem at nose tackle and despite management's putting too much confidence in unreliable inside linebacker Daryl Washington, who hasn't been cleared to return after last year's suspension for substance abuse. Compounding the problem is that Washington almost certainly will get his suspension lengthened because of a domestic-abuse allegation.
Sean Weatherspoon, the team's big offseason free agent signing, was supposed to come to the rescue as the starting inside linebacker. But Weatherspoon couldn't make it through more than a half-hour of the team's first practice before suffering an injury. Several days later, he tried to run again but couldn't.
He did play during part of the Denver preseason game, but it's puzzling that the Cardinals acquired such an injury-prone player for such an important position. Weatherspoon missed almost half of the games he was supposed to play for the Falcons over the past five seasons.
If Weatherspoon turns out to be a bust, their best player at inside linebacker is safety Deone Bucannon, a first-round pick last year and — besides Mathieu — Keim's biggest success in his first three drafts. Bucannon demonstrated last season that he's strong and tough enough to play at the more physical linebacker spot.
But though this issue and many others emerged during a grueling training camp and exhibition season, the Cardinals consider themselves lucky.
As they prepared for the much-awaited season opener against the Saints, Carson Palmer, who's led them to a 13-2 record in his past 15 starts, still was standing, his knee in good working order.
If he can stay on the field for the entire season, the Cardinals have a shot at the title.