Roach is expected to be available when the Bears open the regular season against the Detroit Lions on Sept. 12.
He had been dealing with discomfort in his left knee since early in training camp. Instead of asking Roach to play at 75 percent this season, the Bears opted to perform the surgery with a few weeks left in the preseason, therefore allowing Roach time to heal before the start of the regular season.
Roach is locked in a battle with Pisa Tinoisamoa for the starting spot on the strong side. Both players performed well in the first two preseason games, but Roach's injury likely puts Tinoisamoa in the drivers seat.
"I think it hurts you every day you don't practice, especially when you are competing against somebody who is out there and who is a good football player," Bears coach Lovie Smith said. "We take everything into consideration. We've seen Nick play, and we feel like we have an idea, but whether he is the starter or not, he and Pisa will both play football for us this year."
Jeff Dickerson covers the Bears for ESPNChicago.com and ESPN 1000.