INDIANAPOLIS — The Indianapolis Colts' injury problems aren't going away.

Coach Tony Dungy said Wednesday that starting cornerback Kelvin Hayden won't play against Baltimore on Sunday because of a left knee injury. Dungy didn't provide any additional details and wouldn't speculate how long Hayden could be out.

"Tim Jennings will end up playing in Kelvin's spot and Dante Hughes will be the nickel back," Dungy said.

Hayden said earlier that he hurt his knee when he stepped in a hole on the field during last Sunday's comeback victory at Houston. He had an MRI exam on Monday and did not speak to reporters in the locker room Wednesday.

But as bad as the Colts' long injury list has looked this season, it could be worse.

Three other starters — defensive end Dwight Freeney, cornerback Marlin Jackson and receiver Anthony Gonzalez — also were hurt Sunday. None of the four practiced today, although Dungy expects at least Freeney and Jackson to play against the Ravens.

Jackson sprained his ankle against Houston, and team officials initially feared he had a high-ankle sprain that typically sidelines players four to six weeks.

"He'll be fine," Dungy said. "I can't speak for Marlin, but I think he'll be fine."

Freeney, a three-time Pro Bowler and former league sacks champ, has constantly fought nagging injuries since his rookie season and missed the second half of last season after undergoing foot surgery. This time, he's dealing with a strained hamstring that isn't likely to keep him out too long.

Gonzalez, the Colts' first-round pick in 2007 and an increasing contributor in Indy's offense, is the bigger question. He was diagnosed with a concussion, and Dungy didn't say whether Gonzalez had been cleared to practice or play.

Indianapolis is typically cautious with head injuries and holds players out at least one week before letting them play.

The Colts opened training camp with two-time league MVP Peyton Manning (knee), reigning defensive player of the year Bob Sanders (shoulder), Freeney (foot), starting guard Ryan Lilja (knee) and starting linebacker Tyjuan Hagler (pectoral muscle) on the physically unable to perform list.

Sanders, Manning and Freeney all returned, but Sanders has missed the past two games with a sprained right ankle and is expected to miss at least a couple of more weeks. During his weekly Sunday night show on WISH-TV, Sanders said he was feeling well and ahead of schedule.

Complicating matters has been a rash of injuries to the offensive line. Pro Bowl center Jeff Saturday missed the first two games with a knee injury before returning in Week 3, Lilja still has not been activated, left tackle Tony Ugoh missed one game with a groin injury and second-round pick Mike Pollak, the Colts' projected starter at guard, finally returned from his own knee injury last Sunday.

Ugoh hopes to be back in his usual spot against Baltimore.

"I'm feeling fine, but I've had a couple of days off, so today is the best you're going to feel," Ugoh said. "I'm kind of working my way back in in practice."

Dungy does not believe injuries alone can be blamed for the Colts' slow start.

"That would be an easy way to excuse it," he said. "We have to get more consistent all the way across the board, offense and defense."