ANDERSON, Ind. (AP) Running back Vick Ballard and offensive lineman Donald Thomas are favorites among the most important Colts fans.

Coach Chuck Pagano and his assistants are big supporters. Even teammates vying for those precious 53 roster spots are rooting for them.

After spending nearly two full years working to recover from debilitating injuries, Ballard and Thomas are back at training camp ready to prove they're ready to play.

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''I'm nervous, excited, just a lot of emotions,'' Ballard said after Indianapolis opened workouts Sunday. ''I'm doing a pretty good job of keeping my nerves in check.''

Given the running back's history, there's reason to be unnerved.

As a rookie in 2012, he emerged as a potential playmaker. But during the second week of the 2013 season, Ballard tore the ACL in his right knee at practice. Then on the second day of training camp last year, Ballard tore the left Achilles tendon, ending another season.

Ballard is just one of the players in Indy's group of comeback kids.

There is Thomas, the high-priced free agent who was supposed to be the starting left guard the last two years. Instead, he missed all but two games in 2013 with a torn right quad and then sustained the same injury at training camp last year.

There is 2013 NFL sacks champion Robert Mathis, who hopes to defy the odds by getting back to his game-wrecking form at age 34 after tearing his left Achilles tendon in September.

There's inside linebacker Nate Irving, who finished last season on injured reserve with Denver after hurting his right knee in November, and defensive tackle Art Jones, Indy's prized free-agent in 2014 who was hobbled by a sprained right ankle most of the season.

Not surprisingly, the Colts are playing it safe.

While Jones has been a regular practice participant at Anderson University, Pagano is keeping Ballard and Irving on a sort of pitch count.

And although Mathis has documented his recovery with Internet videos and Thomas has had no trouble walking around campus, both are on the physically unable to perform list.

''That's a tough thing to have that happen to a young player with so much potential like Donald,'' said Todd Herremans, the current starter at right guard. ''I know a lot of people count you out when you get injured. Or you get a certain moniker, like injury-prone. I'm just looking forward to seeing him (Thomas) get on the field.''

Why not?

The Colts know that a healthy Thomas could help solidify an offensive line that has used 18 different starting combinations over the past two seasons, and a healthy Ballard would give them another powerful runner who could help them improve a sub-par ground game.

Mathis' return, of course, would put one of the league's most feared pass rushers back on the field, while Jones should help Indy's run defense.

''I'm feeling great, amazing,'' Jones said after Monday morning's short workout. ''Toward the end of last season, I really started feeling better. But it's absolutely frustrating when the guys depending on you are playing at a high level, and you can't do anything to help.''

Jones isn't the only one looking and feeling good.

Ballard put away the books that helped him bide his time over the past 12 months and got his first touches in 54 weeks Sunday afternoon. Pagano might be his biggest fan.

''We love that kid,'' Pagano said. ''You think about what he did for this football team and in 2012. He's a warrior. He's a great player. He's a great teammate. That's a foxhole buddy - you want to take him downtown with you because you know he is going to have your back.''

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