Now he was about to face reality.
Willis was starting his first game as the San Francisco 49ers' middle linebacker two years ago when he found James barreling toward him on an off-tackle play. It was the kind of moment when Willis expected to justify his value as a big-hitting first-round pick.
Instead, James crashed into him with so much force that Willis blacked out briefly upon impact.
If that play hadn't been humbling enough, Willis found himself racing toward James later in the same game. This time, he took a perfect angle, lowered his shoulders and slammed into James near the goal line. By the time Willis looked up after landing on his back, the official was raising his arms to signal a Cardinals touchdown.
"People kept telling me [James] was done, and I kept thinking, 'This is the same guy?'" Willis said in a recent interview. "That's when I knew this was a grown man's game. And if you're going to play it well, you had better bring it when you're tackling somebody."
Willis can laugh about that moment today because his two Pro Bowl appearances prove he knows a few things about tackling. What he can't do is argue that most of the league is as good at takedowns as he is.
One of the most fundamental aspects of football since the days when Red Grange and Bronko Nagurski were running wild, proper tackling seems to have regressed as the NFL has evolved in recent years. In fact, many people think it never has been worse than it is today.
If that's the case, how bad is it?
Houston Texans general manager Rick Smith said: "Tackling is definitely an art form and, in some ways, it's becoming an aging art form."
Another AFC personnel director, speaking on the condition of anonymity, was even more candid: "There's no question that tackling has gotten worse. And that's because I'm not so sure that you really can teach it. It's about instincts, and there are some people who have them and some people who don't.
"Plus, it hardly ever gets practiced in the NFL. And when you don't do something often enough, you're not going to be very good at it."
Plenty of possible culprits
Lack of practice is actually just one factor in the decline in tackling. For one thing, it doesn't help that the league has seen an influx of incredibly elusive runners through the years.
Coaching philosophies play a role, as well. Spread offensive formations are met with alignments that put more defenders in space, making them more vulnerable. Some defensive coaches emphasize gang-tackling over one-on-one take-down ability.
And good, old-fashioned desire can't be overlooked, either.
"I don't think it would be that hard to tackle a guy if you just attack him," said Minnesota Vikings Pro Bowl running back Adrian Peterson, who has broken many reluctant embraces.
"If a guy doesn't attack me, I can stutter-step or make some moves. But if he comes right at me, it makes it harder for me to do things."
As easy as it is for people to bash today's tackling, it's much harder for them to articulate the rationale behind those criticisms.
After all, the league doesn't keep statistics on tackling -- individual teams do -- so it's an argument that is based mainly on perception. But the important thing to understand about tackling is that subtle details are what ultimately determine whether it's done properly.
As the AFC personnel director noted, "[Pittsburgh Steelers Pro Bowl safety] Troy Polamalu isn't a great tackler by definition because he makes plays by diving at people or throwing his body around. But he gets people on the ground, and that's what you're supposed to do."
Although Polamalu consistently finishes plays, other defenders have noticeable flaws. Some defenders launch their bodies at ball carriers, which can lead to highlight-reel hits -- and to just as many blown tackles. Peterson said he sees more egregious mistakes among cornerbacks, of whom he said, "Some guys are ankle-biters or just don't like contact."
"The main thing I see is players putting their heads down or closing their eyes when they go for a tackle," said 49ers coach Mike Singletary, who was a Hall of Fame middle linebacker with the Chicago Bears from 1981 to '92.
"One of the first things that you have to remember about tackling is that you have to see what you're hitting."
Five fundamentals of proper tackling
Although getting a runner on the ground by any means possible is the goal of any defender, there are other essential fundamentals to tackling.
A proper tackle usually involves a player: (1) putting himself in position to make the play; (2) getting his head across the body of a ball carrier; (3) grabbing hold of the jersey (or "grabbing cloth," as it is called); (4) keeping his feet moving after contact; and (5) taking the opponent to the ground.
Before any of that can happen, a defender must know how to take proper angles to the ball.
To understand the importance of this, just consider how bad angles led to four Pittsburgh defenders missing Baltimore Ravens running back Ray Rice on a critical fourth-and-5 catch-and-run late in the Steelers' 20-17 overtime loss in Week 12.
"That's the most important thing about tackling," said Texans strong safety Bernard Pollard. "If you take a bad angle in this league, it's going to turn into a big play in a hurry."
Pollard should know. Before the former Kansas City Chiefs regular signed with the Texans in September -- and entered the lineup in Week 4 -- Houston had allowed a league-high average of 205.0 rushing yards in its first three games.
The arrival of Pollard gave that defense a 6-foot-1, 224-pound banger, but he wasn't the only reason that unit has allowed just an average of 90.2 rushing yards per game since.
"I think we struggled early because we weren't tackling well," Smith said. "Since you don't practice it at this level -- mainly because you don't want to lose players -- it can take three or four weeks to just get used to doing it."
Smith added that most people in the NFL assume that players are expected to know how to tackle before they reach the league. In fact, it's harder than some might suspect to find players who are used to practicing tackling as frequently as one might think.
It doesn't happen nearly as much in college, where the NCAA limits practice time. Also, collegiate defenses have to cope with the ubiquitous spread offense. That formation, as Texans defensive coordinator Frank Bush said, "makes defenders get used to tackling at all sorts of weird angles."
It also appears that some of today's best tacklers honed their skills with the help of special circumstances.
For example, Willis became a better tackler after breaking a finger on his right hand in his junior year at Mississippi. Because he had to wear a cast, he didn't have the strength to grab runners. A banged-up left knee also sapped his explosiveness.
So Willis decided to wrap his arms around runners the same way he watched his father -- a logger in Bruceton, Tenn. -- wrap his arms around a tree on the job. To this day, Willis exaggerates that motion while tackling to ensure his success.
Hard to pinpoint tackling's "decline"
Atlanta Falcons middle linebacker Curtis Lofton benefited from his own experience in college, although his growth resulted from having to deal with a teammate in practice: former Oklahoma teammate Peterson.
When Lofton was a freshman, he once thought he had a bead on Peterson as the halfback ran around end. Then Peterson blew past him on his way to the end zone.
"Playing against him definitely helped me learn how to tackle better," Lofton said.
That lesson paid off for Lofton as soon as he hit the NFL. He was a rookie starter for the Falcons last season. This year, he's ranked among the league leaders in tackles.
Some might be surprised by his quick success -- he slipped to the draft's second round despite a stellar career at Oklahoma. Peterson said his old teammate excels at tackling because "He doesn't wait for things to happen. He fills the gap and comes right through it."
"The thing that Curtis does well is that he doesn't overcomplicate tackling," Falcons coach Mike Smith said.
"When he gets his read, he goes fast and he runs through ball carriers. Plus, he has such good vision that it helps him see things peripherally and avoid getting caught up with blockers. Those are all marks of good tacklers."
Lofton and Willis are two of the names most commonly mentioned when people start rating the league's best young tacklers. Veterans such as Baltimore Ravens middle linebacker Ray Lewis, Washington Redskins middle linebacker London Fletcher and Vikings cornerback Antoine Winfield also generate praise for their skills.
But a bigger challenge for most observers is determining just when tackling started to decline. After all, it's not as if it has become a less valuable skill as the years have passed.
Singletary actually remembers players hitting every day in practice when he was a star linebacker in Chicago in the 1980s. That was just how former Bears coach Mike Ditka liked to prepare his team.
Other coaches of that era -- such as former 49ers head coach Bill Walsh -- thought it was better to limit contact as the season progressed.
"Even though the 49ers did that, you still saw great tacklers like Ronnie Lott and Keena Turner on their defense," Singletary said.
"That's why I really think your mentality plays such a huge role in tackling. You have to want to do it right."
Singletary also recognizes that tackling in today's game has been affected by changes to the sport. The rules have hindered some of the aggressiveness -- tactics such as leading with the head or horse-collaring are now illegal -- and offensive coaches are far less interested in playing smashmouth football.
"They ran the ball 60 percent of the time back then, and it's a lot easier to make tackles in those close quarters than it is to do it in the open field against Reggie Bush."
The risks, rewards of tackling drills
The lack of practice doesn't help matters, either.
All teams understand the logic behind avoiding contact in the regular season, but there are still moments when it is necessary.
In fact, the Texans' Smith admitted he's never more nervous in a season than when he has to watch goal-line drills in training camp. Every time a play ends in that session, Smith prays all his players get up without the assistance of a trainer.
Singletary, on the other hand, believes heavily in the value of the "nutcracker" drill, which he runs a couple of times a day for the first three days of camp. The drill -- which involves a defender and a ball carrier lining up 5 yards apart and the runner trying to elude the defender in a tight space -- is so old-school that a trainer once asked Singletary how it helps players.
"I told him that for five seconds you're making contact at full speed and you're doing it the right way," Singletary said.
"It helps a guy become a better tackler, and when a guy tackles correctly, there is less chance that he'll hurt himself or somebody else. It's just good for the game."
That's an especially helpful approach when considering whom defensive players are trying to tackle. There used to be a time when ball carriers were easily differentiated -- you primarily had bruisers such as Jerome Bettis, elusive types such as Barry Sanders and hard-charging tough guys such as Emmitt Smith. Now you have more runners who possess all those traits (such as Peterson).
As Falcons coach Smith said, "You have to give some credit to the runners. There used to be four or five guys who were really hard to bring down, but now there are a lot more."
Falcons general manager Thomas Dimitroff added that two- and three-headed backfields also create problems.
"The two-back approach does make it harder to tackle," he said. "When you look at what we have -- with Michael Turner and Jerious Norwood -- that's hard on a defense because you get used to seeing the same thing over and over. If you've been used to seeing a big, durable back and then a speedy guy comes at you, it's going to throw you off."
Read and react
That little bit of confusion can be dangerous for defenders, especially because it leads to hesitation.
I got him down eventually, but he wound up getting the first down. But that's a crucial thing when you're tackling somebody -- you can't be afraid to miss.
”-- Buccaneers LB Barrett Ruud, recalling hesitating before making a tackle on Bills RB Fred Jackson in a game earlier this season
Ruud, who is considered to be among the league's best tacklers, knows what that feels like because uncertainty cost him a tackle in an early-season loss to the Buffalo Bills, a miss that still drives him crazy. It was just a simple swing pass that Bills running back
Fred Jackson caught on a third-and-2, but, Ruud said, "I started thinking too much [on the play]. I was thinking if I do this or I do that, then he's going to get by me.
"I got him down eventually, but he wound up getting the first down. But that's a crucial thing when you're tackling somebody -- you can't be afraid to miss."
Ruud's experience also speaks to one of the subtler factors in declining tackling skills: how coaching philosophies affect it.
When Ruud joined the Bucs as a second-round pick out of Nebraska in 2005, he prided himself on being a secure tackler. But the Bucs played a Cover 2 scheme that relied on having several players rally to the football. So instead of attacking a ball carrier and breaking down -- which is football lingo for steadying your body and lowering your center of gravity to make a tackle -- Ruud was told to fly at runners at angles that always forced the ball carrier back toward the rest of the defense.
It took him a year before he felt comfortable doing that.
Some people also believe the emphasis on forcing turnovers has led to more blown tackles in recent years.
"That's the biggest thing I see," said Houston middle linebacker DeMeco Ryans.
"There are so many people now trying to strip the ball out when they make tackles that they don't wrap up the runner. And once you're doing that, it's easy for a guy to break a tackle."
Passion for the 'lost art'
Ryans is like many of the tacklers in today's NFL who have the right mentality for the job. They want to excel at it, and they're always searching for ways to hone their skills.
Take Baltimore's Lewis, for example.
When the Ravens hired Singletary as their linebackers coach in 2003, he and Lewis met to talk about ideas. Despite being a perennial Pro Bowler, the first thing Lewis said was, "Everything you know, I want to learn."
Lewis was just as intense on the practice field later that week. In fact, he came over to Singletary midway through one session and said he was trying so hard to follow Singletary's instructions that Lewis' calves were throbbing. After watching Lewis some more, Singletary realized the problem: Instead of staying on the balls of his feet, as Singletary had advised, Lewis was standing on his toes when lining up for plays.
"That's how much he wanted to improve," Singletary said. "His calves were cramping up, and he was still trying to do it right."
Singletary has been just as meticulous in his approach to helping Willis.
"I always had people telling me 'good play' when I did something on the field but it wasn't that way with [Singletary]," Willis said.
"Even if I made a tackle for a loss, he would say, 'You don't have to do it that way.' Or if I made a great play, he would say, 'Pat, that's not it.' Now I've gotten to the point where I know when I'm not doing something correctly."
What Willis understands is that his coach played at a time when tackling wasn't taken for granted. That seems to be the biggest problem with the skill today -- that it's becoming a lost art because there are too many reasons not to focus on it.
That also happens to be one reason so many NFL people don't foresee tackling improving any time soon. The passion for the art isn't what it used to be.
That's why the 49ers are happy to have a player such as Willis. He's always reminding himself about the importance of angles, and he has even agitated some teammates with his fervor for contact in light drills.
But every time a 49ers player shoots him a dirty look after Willis has thumped him in practice, Willis explains that he doesn't want to be another player with bad tackling habits.
"When people see me on film," Willis said, "I want them to know I'm playing this game the right way."
Senior writer Jeffri Chadiha covers the NFL for ESPN.com.