Peyton Manning's streak of 160 straight starts doesn't appear in serious danger after minor knee surgery.

But the superstar quarterback's medical problems — an infected bursa sac in his left knee — only adds to the long injury list the Indianapolis Colts will face when they open training camp July 25.

Not only will Manning be unavailable, but so will defensive end Dwight Freeney, wide receiver Marvin Harrison and safety Bob Sanders, the NFL's defensive player of the year last season.

The Colts say Manning can make a "full and complete return" in four to six weeks. That means, at worst, he can open the season against Chicago the night of Sept. 7, when the Colts unveil their new stadium in a replay of the 2007 Super Bowl. Given Manning's durability, there's a chance he could play the last exhibition game or two.

"There is no sense of any untoward condition with this," team president Bill Polian told The Associated Press today.

Still, it leaves the Colts with Jim Sorgi as the only experienced quarterback when the team goes to training camp. Also on the roster are Josh Betts, Ben Roethlisberger's backup at Miami of Ohio, who spent last season on the practice squad, and Adam Trafalis, an undrafted rookie from San Jose State.

Polian said he will not sign another quarterback.

Sorgi has never started a game in four NFL seasons and has played mainly in relief of Manning in blowouts or in late-season games when the Colts have clinched playoff berths and seedings. In 14 games, he has completed 77 of 126 passes for 751 yards, six touchdowns and one interception.

A bursa sac provides a cushion between bones and tendons around most major joints in the body. They can become inflamed, which is what happened to Manning.

It is not unusual for athletes to play with inflamed bursa sacs. In 1987, Joe Montana played most of the season with one around his throwing elbow. He finished the season, 12 games that year because of a strike, with 31 touchdown passes, then a San Francisco team record and the best total of his 16-season Hall of Fame career. He had surgery after that season.

Manning has started every game in the 10 years he's played in the NFL, with his consecutive starts second to Brett Favre's 253. If Favre makes good on his intended desire to return, his streak could be extended — or broken.

"I'm going into my 11th year. I'm 32, but I really feel I'm in a younger body than that," Manning said last week. "I feel I'm in a 28-year-old body because I've had great protection from my offensive line. I feel that's hopefully going to allow me to play a number of more years."

Another injured Colt is starting linebacker Tyjuan Hagler, who has a torn pectoral muscle and is expected to start camp on the physically unable to perform list.

So are Harrison, Sanders and Freeney.

Harrison, 35, appears to be of the most concern. He missed most of last season with knee problems, including one with a bursa sac. He had arthroscopic surgery on his right knee in January and has been rehabilitating an inflamed left knee. He is probably the best receiver of the last decade with 1,042 career receptions for 13,944 yards and 123 touchdowns.

Freeney had surgery after a season-ending injury to his left foot last November. Polian said the only question is his conditioning level.

Sanders had shoulder surgery in the offseason.