Marvin Harrison's knees are healthy enough to play football again. Getting back in sync with the Indianapolis Colts' high-scoring offense may take a little more patience.

The eight-time Pro Bowler seemed to enjoy himself Friday, defying the doctors' early prognosis by returning from offseason knee surgery for Indy's first training camp practice.

"It was good to see him smiling and running easy," coach Tony Dungy said. "For me, I try to read his face. When he's smiling, things are pretty much normal."

Harrison wasn't the only one smiling Friday.

As he trotted onto the field in his familiar No. 88 jersey, nearly 1,000 fans chanted his name. They cheered virtually every time he got his hands on the ball _ even when he was catching passes from the equipment staff.

It was a welcome respite for a Colts team that is already banged up.

Six players, five of them starters, were placed on the physically unable to perform list before practice opened. The most notable names: Two-time league MVP Peyton Manning, 2007 NFL defensive player of the year Bob Sanders and former league sacks champion Dwight Freeney.

As recently as a June mini-camp, Dungy said Harrison would likely join his high-profile teammates on the PUP list, meaning the Colts would have started practice without their career leaders in passing, receiving and sacks.

Earlier this week, though, Dungy said the medical opinion had changed and Harrison might be available opening day. On Friday morning, Harrison made it reality.

The usually quiet Harrison declined to take questions after the workout but the Colts liked what they saw from their 35-year-old teammate.

"I thought he looked good," tight end Dallas Clark said. "He's like anyone who hasn't been on the field for a while. I wish it was like riding a bike, but the things we do, the footwork and stuff, that's not natural and that's why you practice. He'll come around like everyone else here."

An aspect of the workout that Dungy described as "less sharp" was Indy's adjustment to its missing stars.

Manning had surgery July 14 to remove an infected bursa sac from his left knee and missed the start of training camp for the first time since 1998, when he was an unsigned rookie. He's expected to be out four to six weeks and his absence gave longtime backup Jim Sorgi a rare opportunity to work with the Colts' regular starters.

Behind Sorgi are two newcomers. NFL veterans Quinn Gray and Jared Lorenzen were only signed Thursday and are still learning the offense.

"It's different," Clark said. "It's just when you've been used to that (having Manning), it's different. It's hard to explain, but we're going to be fine."

Last season, the Colts were ravaged by injuries.

The two most significant were to Freeney, who missed Indy's last eight games after having foot surgery, and Harrison, who missed most of the season after Denver's D.J. Williams rolled into his left leg in Week 4. After that, Harrison, who rarely takes plays off, even in practice, was only on the field sporadically.

Yet the Colts continued winning games. They finished 13-3 and won their fifth straight AFC South title before losing to San Diego in the playoffs _ a game in which Harrison did play.

Throughout the offseason, Harrison continued rehabilitating the injured left knee and then had surgery on his right knee. He also was interviewed by police about a shooting near his North Philadelphia car wash in the spring, but wasn't arrested or charged.

"Marvin did fine," Dungy said after Friday's practice. "He did all his work, took his normal turns. I think we're assuming everything's fine until we see otherwise."

Dungy said the Colts will monitor Harrison's progress closely, although there are no immediate plans to scale back his work.

Still, his return will change some things. Reggie Wayne, who made his second straight Pro Bowl appearance after catching a career-high 104 passes and leading the league in yards receiving (1,510), expects fewer passes coming his way this season.

But with Harrison healthy and a receiving corps at full strength, Dungy likes his chances.

"You're dealing with a rare guy in Marvin," Dungy said. "You saw it with Jerry Rice and a few other guys. You know when we went back to the first four games on tape, there was nothing different than you could discern from 2003 or 2005, so we expect him to play the same way he's been playing all these years."