Owner/general manager Jerry Jones expressed confidence that Colombo would be prepared to play in the Sept. 12 season opener against the Washington Redskins.
"Five particles were there to be scoped out," Jones said during Monday afternoon's practice. "That's the good news, because he's been playing with that type of situation probably for the last couple of years.
"One really was limiting of him and we made note of it and we'll take those out. I don't have exactly how long he'll be out, but those things have a time from 10 days to two weeks, within that time frame. But actually it was good news."
Colombo's knee locked up during Sunday afternoon's practice. He was carted off the field after practice and flew to Dallas to have an MRI and the operation. The original timetable for Colombo's return was two to four weeks.
Alex Barron, the backup for both tackle positions, hasn't played or practiced since spraining his ankle in the Aug. 8 Hall of Fame Game. Jones said Barron is close to returning and might be able to play Saturday against the San Diego Chargers.
Regardless, the Cowboys will start 2009 third-round pick Robert Brewster, who worked with the starters Monday. Brewster missed all of last season with a torn pectoral muscle. Rookie sixth-round pick Sam Young also will see action at right tackle.
Jones said quarterback Tony Romo's playing time could be limited more than normal for the third preseason game if the Cowboys are forced to start an inexperienced right tackle.
"We'll look and see," Jones said." We'll make sure we keep Romo off his back as much as we can."