After a while, it becomes difficult to differentiate one training camp from another. The faces change, but the storylines ring familiar.

Most players, of course, don't see their careers as recurring NFL anecdotes. Every story has its protagonist. But introspective players such as Nolan Carroll know that their plights, in most cases, aren't unique. They understand that starters who are attempting to reclaim their jobs after season-ending injuries are about as common as Coca-Cola.

A year ago, Carroll was locked into one of two outside cornerback spots. He had what coaches almost unanimously said was the best offseason for any returning player. He would go on to have a solid season - a good one in comparison to counterpart Byron Maxwell - until he broke his ankle on Thanksgiving.

Carroll's free-agent stock plummeted. He signed an incentive-laced one-year deal with the Eagles and spent most of the offseason rehabbing as other cornerbacks - most of them recently acquired - practiced in Jim Schwartz's new defense.

Head coach Doug Pederson all but gave Leodis McKelvin one of the starting jobs before minicamp broke in June. Fellow free agent Ron Brooks received valuable first-team snaps. And rookie Jalen Mills took advantage of his opportunities to impress the coaches.

Of the healthy cornerbacks, Eric Rowe struggled. He filled in for Carroll after his injury and showed enough as a rookie that one of this year's openings was seemingly his to lose. But nothing can be taken for granted in the bottom-line NFL, a lesson Carroll has learned after six up-and-down seasons.

"I don't think [the injury] set me back at all," Carroll said on Monday as the Eagles opened training camp. "But, at the same time, I don't feel like I'm entitled to anything just based off of things that happened last year. I go through it the same way every year, thinking the same way. I'm going to compete."

Carroll was one of the few established veterans who attended the early portion of camp that is usually reserved for quarterbacks, rookies and fringe roster types. The rest of team reports on Wednesday and will practice full on Thursday.

JaCorey Shepherd, like Carroll, watched most of spring team drills from the sidelines as he neared his return from the anterior cruciate ligament he tore last August. It's been a long road - one traversed by many - but Shepherd felt snake bitten. He had ascended to the top of the depth chart at slot corner, despite being a sixth-round rookie, just a week before his injury.

"It was pretty tough for me this year," Shepherd said, "but it panned out in a good way."

Shepherd isn't settling for the nickel corner role. He wants to start on the outside and said that he has as good a chance as any of the competitors.

"Hell, yeah. It's open, baby," Shepherd said. "No job is taken yet, and that's the way I'm going to attack it. Regardless of how many [defensive backs] we have in the room, I know I'm going for a starting spot."

Carroll and Shepherd, given full clearance during the break, are here early to play catch-up, but they have plenty of time to get back in the conversation. While McKelvin, who played for Schwartz in Buffalo, may appear to have a leg up, it's not as if his free-agent contract assures him anything (Re: Maxwell).

"I think there's great depth there," Pederson said of the competition at corner. "I think with the addition of Jalen Mills it brings some good competition there. You've got Ron Brooks sitting over there. Nolan is coming off the injury, and I expect him to fully compete at that spot."

Pederson failed to mention Shepherd - understandable considering his recovery - but Rowe's absence in his response could be telling. The corner clearly had issues in the spring transferring to Schwartz's new scheme, but writing off his chances at this early stage would be foolish.

Rowe is a physical corner, and as Pederson noted, practicing in pads and without restriction should allow him to be more aggressive.

"He's learning a new defense and new techniques this year," Pederson said. "And there were some hiccups in the road a little bit this offseason, and he was pulled back a little bit. But you just want to see that growth and that development with any player on your roster."

The Eagles corners will have to defend more using man-to-man press technique than they did the defense of former defensive coordinator Bill Davis. They should have more help over the top from the safeties, but they could be more susceptible on inside routes.

"A lot of what we now do is dependant upon the pressure that we get, so as corners we have to be able to do our things on the outside," Carroll said. "If we let them inside there's really no one there to help us."

Davis and Chip Kelly favored rangy corners on the outside. At 6-foot-1 and with long arms, Rowe fit the mold. Schwartz, who talks to reporters on Tuesday, has said that he doesn't place as much emphasis on size. His endorsement of the 5-10, 185-pound McKelvin suggests as much.

Shepherd said that the previous regime also projected him to the outside - it should be noted that defensive backs coach Corey Undlin returns - but Schwartz's less dogmatic approach could benefit the 5-11, 199-pound corner.

"I pretty much think I can get out there and cover whoever," Shepherd said. "I'm big enough, fast enough. It's just getting thrown out there and playing."

He'll get his opportunities, as will Carroll. But neither has the market cornered on comeback stories, nor will they get the benefit of time. The best routinely win.

@Jeff_McLane