An NFL roster is a living, breathing thing. The 53 players who begin the season on the active roster will change throughout the course of the season, and it's often up to the pro personnel department to help identify players who can be imported when roster spots open up. This season, several players have made an immediate impact on the Eagles despite not beginning the season with the team.

For one, Owen Schmitt has filled in for Leonard Weaver as the starting fullback admirably after Weaver was lost for the season in Week 1 with a torn ACL. Schmitt was signed to replace Weaver only a few days later and was immediately inserted into the starting lineup. Since, he's been a key cog as both a run blocker and a pass protector, and he's also impressed as a receiver coming out of the backfield with 17 catches for 131 yards, including his game-sealing 5-yard touchdown reception in last Thursday's 34-24 win over the Houston Texans.

"Owen's done a heck of job," said head coach Andy Reid. "One advantage Owen had was he was in Coach (Mike) Holmgren's system in Seattle, so the terminology wasn't completely foreign to him. But at the same time, you've got to come in and you've got to establish yourself and get the respect of the players. And he did that, right from the first week. He had some big catches in the first week, and big blocks in the first week. So, he's been able to maintain and done a nice job."

Schmitt said that from the moment he joined the Eagles, he's felt like a good fit.

"Just being accepted here is a big thing for me and I'm glad," he said. "It's been open arms, so it's been fun."

Of course, Schmitt's not the only one. When Mike Bell wasn't performing quite up to expectation, general manager Howie Roseman was able to swap him for Jerome Harrison, formerly of the Browns. Since the trade, Bell has 16 carries with the Browns for 22 yards (1.4 yards per carry) and Harrison has 17 carries for 137 yards (8.1 yards per carry). Harrison has been so productive on a per-play basis that the Eagles are struggling to find ways to get him the ball enough.

"We try to find spots to work him in," said Reid. "We're switching personnel groups so much and he's definitely worthy of playing more. It's not anything from his effort or ability. It's just hard at times to take (LeSean) McCoy off the field when he's in the swing of things and doing as well as he's doing. But it seems like every time Harrison gets in, he does a good job. And we need him. We need him to spot McCoy."

There have been some other players who have made impacts like Chad Hall, who began the season on the practice squad, and tight end Garrett Mills, but perhaps the biggest success story of the personnel department finding a diamond in the rough is safety Colt Anderson. For a special teams unit that had struggled in coverage, the addition of Anderson, signed from the Minnesota Vikings practice squad in Week 10, has been a godsend.

"I think bringing Colt Anderson on our team has made a big difference," said special teams coordinator Bobby April about the man who's lead the team in special teams production points in three of his four games as an Eagle.

When recounting the process of bringing Anderson on board, April said that Roseman and his staff had been eyeing the Montana product for a while, hoping for a chance to bring him to Philadelphia.

"Howie came to me ... and said, 'Look, I got this kid I really like. I'm going to make up some of his preseason game films, put it on a reel, would you watch it for me and tell me what you think?'" April said. "I looked at (the tape) and I went, 'Woah.' I said, 'Man, if we can get this guy, he can help us. He can do a lot of things. He's a playmaker, he's tough, he's aggressive. He really knows how to play. It was a week or two later that we signed him.

"I think Howie may have wanted to get him in earlier, we just couldn't."

With the season heading into the stretch run, the personnel department hasn't slowed its work. April called them "grinders," adding that they're perpetually burning the midnight oil. And though you cross your fingers and hope that no more significant injuries are forthcoming, there are always surprises. But having seen the success of guys like Schmitt, Harrison and Anderson, Eagles fans can rest assured that if anything does go wrong, Roseman, director of pro personnel Louis Riddick and crew will be more than prepared.

-- Posted by Bo Wulf, 4:47 p.m., December 6