Troy Polamalu's the heart and soul of the Steeler defense, and without him they aren’t a playoff team. With him, they are. Simple as that. A lot is riding on his return to health in Pittsburgh in 2010. Gerrit Ritt breaks down the other key stars who must return to the field this year after injuries crushed their teams last season.

The six-time Pro Bowler’s been dealing with a variety of injuries throughout his career, with his hip being the latest issue. It caused him to miss four games near the end of last season, but if he can return at full strength and decides against retirement, the Ravens will have one of the top defenses in the NFL yet again and will be a force to be reckoned with in the AFC.

Welker (pictured) probably won’t be ready to start the season, but he’ll assuredly be a factor once the games really mean something. He’s the best possession receiver in the NFL, with 111 catches or more in each of the past three seasons. Just ask Patriots QB Tom Brady how important Welker is.

Missed most of the second half of ’09 with a broken ankle. With only one carry in the season's last five games, the Falcons struggled and just barely missed the playoffs. If he’s 100 percent, though, this is an extremely dangerous team, as they'll be getting explosive wide receiver Harry Douglas back from injury as well.

Injuries have always been a part of Sanders’ career, but the Colts are proving they can win without him. How will that affect what happens to the All-Pro safety in the seasons to come? Will he be with them much longer?

Ricky Williams is still in town, meaning Brown won’t have to be a feature back with 25 touches each week. Fantasy owners may hate that, but Dolphin fans should be overjoyed, as a full strength Brown for 12-15 touches a game should be able to do some amazing things for Miami.

The Giants' pass defense went in the tank last year without Kenny Phillips, who only played two games due to a gimpy knee. Somehow, though, he had 13 tackles and two picks in those two games. New York's secondary never filled his void, finishing 30th in scoring defense and giving up 40-plus points five times.

The neck injury that cost Slaton five games last year could eventually cost him his job, too. Arian Foster wants his shot to be the man in Houston's backfield, and if Slaton’s not back at 100 percent, he might just get it. Without a running game, the Texans became a strong passing offense, albeit one-dimensional.

He only played in one game for the Chargers last season thanks to a torn triceps muscle, but the Broncos are taking the chance he can improve their front four. If this Denver team can figure out how to pressure the quarterback, they may go places.

He didn’t even survive long enough to catch a ball last season, as he was injured before Week 1 and only saw action in one game late in the year. With Pierre Garcon and Austin Collie proving they can play too, it won’t be so easy for Gonzalez to earn a starting spot again. But a healthy Gonzalez gives QB Peyton Manning yet another aerial weapon.