Gone are the days of rookies sitting on the bench and waiting two or three years for their opportunity to play. Given how much first rounders make and the fact that their contracts usually expire by the end of their third year, teams have no choice but to rush youngsters onto the field.
So when training camp opens up in July, expect a good portion of this year's incoming rookie class to contend for starting spots.
In fact most of the high-profile battles heading into training camp pit a 2012 rookie against a veteran. But not all of those battles feature rookies: Some include second- or third-year players fighting for a starting gig.
So which vets are in danger of losing their jobs this fall? Check out this list.
Replacement: Prince Amukamara
This list starts off with a quasi-starter who is seriously in danger of losing his job.
Thomas missed all of 2011 with a torn ACL, but prior to that he had been a two-year starter for the Giants. His age is just as important to his claim to the gig: He's only 27.
But the Giants didn't spend a reasonably high first-round pick in 2011 to have Prince Amukamara sit on the bench. Besides, he's bigger than Thomas and despite breaking his foot last year, he gained a ton of experience during the 2011 season and throughout the Giants' Super Bowl run.
Considering how much the Giants are paying Corey Webster and how well he sometimes played last year, his job isn't up for grabs.
Only Thomas' is.
Replacement: Melvin Ingram
There are actually several possible contenders for both the spot of "incumbent" and "challenger" on the Chargers' weak-side outside linebacker spot, opposite Jarret Johnson.
Antwan Barnes gave excellent production in 2011, recording a team-high 11 sacks.
But in 2010 it was Shaun Phillips who led the Chargers with 11 sacks and earned a Pro Bowl spot. So considering his production and versatility, the Chargers had to expect Phillips would be the starter in 2012.
That changed in April when the Chargers were fortunate enough to have Melvin Ingram land in their laps. He's younger and doesn't have nearly the same amount of wear-and-tear. And since both Barnes and Phillips are free agents after 2012, they may want to put him on the field sooner rather than later.
Replacement: Willie Colon
After all their mixing and matching over the past few years, there will be major changes to the Steelers offensive line in 2012. David DeCastro figures to have right guard already locked up just because of his college résumé, but the other guard spot is a bit more of a question mark.
Reports out of Pittsburgh have former starting tackle Willie Colon moving to the inside to play guard.
If Colon—who played very well in 2008 and 2009 but has basically missed the past two seasons with injuries—can hold down the right guard spot, it will push out Ramon Foster.
That may be a bit of a surprise considering how solid Foster was in 2011 and the fact that the Steelers just gave him $1.26 million this offseason.
But Colon's footwork and strength suggest that he is an upgrade and can improve that fairly mediocre running game and less than mediocre pass-protection.
Replacement: C.J. Spiller
For the past three years, Fred Jackson has been one of the "feel good" stories of the NFL: a small college player who went undrafted, played in the arena league and NFL Europe, then became an NFL starter and at one point last year was the league's leading rusher.
But his rise wasn't always a "feel good" story for the Bills front office.
After all, the year that Jackson first became a 1,000-yard rusher came just months after Buffalo spent a ninth-overall draft pick on another running back, C.J. Spiller.
Spiller has flashed moments of excellence, most recently a 111-yard rushing effort in a blowout of Denver during Week 16. But he's roving dangerously close to "bust" territory. 2012 must be a big year for the Clemson product.
That fact suggests the Bills and G.M. Buddy Nix will do everything possible to put him in the starter's role. And given his tremendous speed and athleticism, he should grab it in training camp. After that, however, who knows.
Replacement: Jamar Chaney
Many people placed the blame for the Eagles' 2011 defensive woes on the middle linebacker position: well, aside from blaming Juan Castillo.
Philly seemingly corrected their problems this offseason by acquiring DeMeco Ryans from the Texans, but it would be a mistake to completely forget about the man who held down the middle linebacker job late in the season.
Jamar Chaney did a more than adequate job playing inside last year. That makes him a good candidate to unseat Brian Rolle, who played the weak-side backer position in 2011.
Both Rolle and Chaney are very young (Rolle was a rookie in 2011), so this isn't a classic veteran vs. rookie showdown. But Chaney's quick recovery from offseason neck surgery shows that he is 100 percent and a serious threat to taking that weak-side backer spot.
Replacement: Whitney Mercilus
The Texans defense is really stacked and seems poised for a run towards the Super Bowl. That comes even after seeing their former centerpiece Mario Williams bolt town for Buffalo.
Part of the reason why the Texans didn't even try to match his big contract was because of the man who replaced Williams throughout 2011.
Connor Barwin played so well, though suffering that season-ending pectoral injury. He had 11.5 sacks in 2011 and was named AFC Defensive Player of the Month in November.
But even he seems replaceable now that the Texans were able to steal Whitney Mercilus towards the end of the first round of the draft.
Mercilus is so talented and so athletic that Wade Phillips will be dying to get him on the field in 2012.
Sure, he could enter games in pass-rush-only situations, much like Aldon Smith did for the 49ers last year, thus keeping Barwin and Brooks Reed as the starting outside backers.
But Mercilus isn't nearly as raw as Smith was and with Barwin's contract expiring after 2012, the Texans will have leverage on those negotiations if Mercilus is able to steal snaps away from him.
Replacement: Michael Floyd
Here's a case where a starter being "squeezed out" is actually a benefit to all parties involved: the incumbent, the challenger and the franchise.
Former third-round pick Andre Roberts had a pretty solid season in his second year with the club, nabbing 51 catches for 586 yards. But he never seemed to be the ideal receiver opposite Larry Fitzgerald. This slot is a much better role for him to play.
Fortunately, the addition of Michael Floyd, via April's draft, should enable Roberts to switch inside.
Floyd is the big, physical, fast receiver who can take a great deal of the pressure off of Larry Fitzgerald and in turn, open things up for Roberts inside on slants and posts.
Fitz, Roberts and Floyd all will come out ahead if Floyd is able to earn that No. 2 role. And so will Kevin Kolb.
Replacement: Morris Claiborne
This scenario is already starting to play out.
Reports out of Big D have Jenkins very unhappy. The signing of Brandon Carr and the selection of Morris Claiborne are the main reasons why. Jenkins' comparatively low salary (just over $1 million for 2012) can't help either.
But there is no guarantee that Claiborne will be an instant fit in the Dallas defense or the NFL in general. Just because Patrick Peterson was, doesn't make it a no brainer.
So the Cowboys will certainly hold onto Jenkins for the time being. And they should.
Still, despite Jenkins' veteran status, Claiborne will push him and make a hard charge for the job, regardless of his learning curve. It's a good bet that by Week 1, Jenkins will be relegated to the team's third nickelback...unless, of course, they trade him.
Replacement: Shea McClellin
The Bears brought back Idonije, who has been a member of that defensive line since 2004, for one more season.
Clearly, however, he wasn't in their long-term plans. And even more proof was dealt on draft day, when the Bears (certainly in need of help at other spots) spent their top pick on Boise State product Shea McClellin.
And while McClellin is not guaranteed to develop and learn in time to start, it's beginning to look that way. Even if he doesn't come from Alabama or Wisconsin or USC.
Still, just because Idonije will ultimately be pushed out of that starter's job doesn't mean he won't see the field. He'll be a great rotator and provide excellent depth. Nevertheless, McClellin figures to be the regular bookend rusher to Julius Peppers for 2012 and beyond.
Replacement: Cameron Heyward
It shouldn't be that surprising to see another entry for the Steelers here. This team will be in serious transition in 2012 and (although they'll still contend for the AFC North) will ultimately go through some growing pains.
The most noteworthy of those will probably be at inside linebacker where James Farrior is gone, but don't overlook the defensive end spot as well.
After years of injury woes, Aaron Smith has finally retired and the man who played opposite him on that Super Bowl XLIII team, Brett Keisel, might also be squeezed out.
Keisel has struggled with knee, groin and back issues the past few seasons (he's missed 14 games the last four years) and will turn 34 in September.
With Ziggy Hood already locking down that left defensive end spot, the Steelers' other recent first-round defensive end selection, Cameron Heyward, might nab the job, pushing Keisel to a rotator rather than a starter.
Replacement: Jon Baldwin
Certainly this entry is contingent upon Dwayne Bowe either signing his tender or being given a new contract. I expect he will ultimately be re-upped. So, assuming he does...
The Chiefs will most likely pay Breaston the $1.3 million roster bonus he's due—every team needs three or four capable receivers—but his place as the team's No. 2 option is in serious jeopardy.
Jon Baldwin may have come into the NFL with some question marks about both his game and his attitude, but after a rocky start (that training camp fight with Thomas Jones), he started to adjust.
By season's end he was on the field more. And with his frame, speed and hands the Chiefs really should do whatever they can to create spots for him.
To do that (again, assuming Bowe re-signs) Breaston will be pushed to the third option and technically out of the starter's role.
Replacement: Ryan Broyles
Many NFL offenses don't have only two starting wide receivers.
Take the Saints for instance. They may employ a fullback at times, or two running backs at other times, but more often than not they have three wide receivers on the field, as well as Jimmy Graham.
The Lions are similar. They routinely have one or even empty backfield sets. So technically, the team's "No. 3" receiver can really be considered a starter.
Such is the case with Nate Burleson, who is probably already the third wide receiver on the Lions' depth chart behind Calvin Johnson and Titus Young.
Still, despite Burleson's veteran status and the solid numbers he put up in 2011 (73 catches, 757 yards) his role there might also be short-lived.
Although he had ACL surgery recently, rookie Ryan Broyles has to intrigue Jim Schwartz and offensive coordinator Scott Linehan. Had he been healthy, he very well could have been a high first-round pick, so to land him late in the second round was a steal.
There was talk of Broyles ultimately beginning the season on the PUP list, but he's holding out hope that he'll be ready by Week 1. If that's the case, and he does get in solid practice time, he could push Burleson further down the depth chart.
Replacement: Daniel Thomas
In 2011 Bush had the best (statistical) year of his career. Since he is finally healthy, there's no reason to think he can't have another productive year for the revamped Dolphins.
But Daniel Thomas, the second-round pick from 2011, is clearly the future in Miami and at times last year, looked really solid and versatile.
With a year under his belt and another full training camp, Thomas should be able to steal more carries away from Bush.
And despite the mini-resurgence Bush had in 2011, the new regime in south Florida is probably quietly hoping that Thomas can usurp the former Heisman trophy winner for the label of "starter."
After all, staying healthy has never been Bush's strong suit and at 6'0", 230 pounds, Thomas figures to be much more durable.
Replacement: Brandon Weeden
I suppose that technically, Colt McCoy is the Browns' starter, but few, if any, NFL teams have a less entrenched quarterback.
It seems that ever since Mike Holmgren and Pat Shurmur took over, McCoy's days in Cleveland have been numbered. And further proof of that came when the Browns spent a first-round draft choice on Brandon Weeden.
So an interesting battle for the starter's job is already underway in Cleveland, and while I do think McCoy does have a very promising future in the NFL, it's not going to be with the Browns. There's just too many things working against him, including his size, arm strength and that whole messy situation regarding his concussion last year against Pittsburgh.
It's unlikely that the Browns will declare Weeden the starter anytime soon: He's still very raw and the Browns would probably like the rest of the NFL to think McCoy is still in the mix so he has trade value.
But by the middle of the preseason, Weeden will seem a more natural fit to the West Coast scheme and take over the starting role.
Replacement: Jake Locker
The most intriguing quarterback battle of this preseason takes place in Tennessee this year, where Matt Hasselbeck is the incumbent, beaten-up veteran, and Jake Locker is the fresh, extremely talented but raw youngster.
Last year, given the absence of a real preseason (no OTAs, minicamps or rookie camps because of the lockout) Locker really had no shot of beating out Hasselbeck for the starter's job.
But now that he has a full offseason and did play quality minutes in 2011 (and showed some real efficiency at times), he is poised to overtake Hasselbeck.
The thing that ultimately gets him over the hump, however, has to be his athleticism. Locker is much more mobile and can throw on the run better than Hasselbeck.
In an AFC South that features one of the deepest and best pass-rush units (Houston) in the NFL, that will be key to the Titans contending.