Source: Forte had knee surgery

Chicago Bears running back Matt Forte underwent arthroscopic surgery on his left knee within the past two weeks, a source close to the player confirmed Thursday.

Forte admitted to suffering a medial collateral ligament sprain after the Bears' 25-19 victory over the Seattle Seahawks on Sept. 27. It was an injury former offensive coordinator Ron Turner cited as a reason for the Bears' mediocre running attack.

"I think there was a drop-off [after the MCL injury], definitely," Turner said after the Bears' season-ending victory in Detroit. "I don't think he had the acceleration or the burst we normally see from him. Yeah, it definitely had an effect."

After rushing for 1,238 yards as a rookie in 2008, Forte slumped to 929 yards this season. He averaged 3.6 yards a carry, down from 3.9 in 2008.

The story was first reported by the Chicago Tribune.