ANDERSON, Ind. -- Colts coach Jim Caldwell isn't ready to say how much time Jeff Saturday might miss.
Jim Irsay is.
The Colts owner told reporters Wednesday that Indy's Pro Bowl center could miss two to six weeks after having arthroscopic knee surgery to remove what the team described as a "loose body."
"We've seen guys come back in two weeks, you see some guys come back in six weeks," Irsay said. "You're hoping it's the shorter side of the scale."
Caldwell would not say how or when Saturday hurt his knee, but that he believed it occurred over time.
The Colts have not said which knee Saturday hurt, and several messages have been left by The Associated Press with Saturday's agent.
Still, Caldwell is leery of establishing a return date. When Saturday tore the medial collateral ligament in his right knee during a 2008 preseason game, the veteran opted against having surgery and returned to the starting lineup Sept. 21.
Total absence: 28 days.
"I couldn't give you a timetable, I haven't heard any specifics from a doctor," Caldwell said after Wednesday morning's practice. "But he's always been a quick healer."
The Colts are hoping that will be the case again for the 35-year-old Saturday, who has been the mainstay of the Colts' offensive line for a decade, logging nearly as many Pro Bowl appearances (four) as missed games (six) since winning the starting job in 2000. He's become one of Peyton Manning's best friends, the second-longest tenured Colts player behind Manning and most people can't even remember the last botched snap he's had.
So when third-year center Jamey Richard lined up with the Colts' starters Wednesday morning, it looked strange.
Richard has made seven career NFL starts, four at center -- all in place of Saturday in 2008. Though he hasn't started a game since November 2008, Richard insists he's ready.
"I have the responsibility of making those [blocking] calls," he said. "That's put on the center, and that's me. It's just something you've got to learn."
Next in line would be Mike Pollak, the Colts' second-round pick in 2008. He was considered one of the nation's top college centers but with the Colts he moved to guard where he's played exclusively over the last two seasons.
"It's been different because I really haven't worked [at center] since college," Pollak said after lining up at center with the second-string offense Wednesday. "But it's like riding a bike."
Caldwell hasn't decided what he'll do in Sunday's preseason opener against San Francisco.
Traditionally, the Colts play starters about 10 plays in the first preseason game, but a suddenly thin offensive line could change the script.
Saturday has missed three consecutive days of practice with his injury.
Left tackle Charlie Johnson, the man responsible for protecting Manning's blind side, was carted off the field during Friday's practice and hasn't been seen since. He has a sprained right foot, and the Colts haven't said when Johnson will return though Caldwell acknowledged Johnson was getting better.
Right tackle Ryan Diem has skipped the three morning workouts this week after his wife delivered the couple's first child.
Rookie guard Jacques McClendon, a fourth-round pick, has been out all week with an undisclosed injury and things were so bad that the Colts have brought in reinforcements the last two days.
They released guard Andy Alleman after the veteran hurt his back, replacing him with undrafted rookie James Williams on Tuesday morning. They also added center Adrian Martinez, claiming the rookie off waivers from Seattle.
"I told the guys there would be some adversity in training camp," Caldwell said. "The best thing is if you can come out of camp with a little more experience and depth, and we've had that happen before. We hope that can happen again. But we've got to keep on getting better. No excuses, just keep getting better."
The Colts expect nothing less.
"It's tough, [Saturday] is the foundation of our offensive line," Pro Bowl tight end Dallas Clark said. "What he brings is consistency, his level of play, all those intangibles are just invaluable. It's definitely the next-guy-up theory, but it's going to be tough without him."