Detroit Lions safety Louis Delmas underwent a surgical procedure on his left knee, the club announced Wednesday.
Delmas, who missed the last five regular-season games of the 2011 campaign with a right knee injury, has been sidelined for most of training camp while dealing with left knee soreness.
"Louis Delmas had a surgical procedure done yesterday by Dr. James Andrews to assist in his recovery from knee soreness that developed early in camp," said Lions vice president of communications Bill Keenist in a statement.
No timetable was given for Delmas' recovery.
A second-round selection (33rd overall) of the Lions back in 2009, the 25- year-old Western Michigan product has started all 41 games he has appeared in and has 163 tackles, three sacks and two interceptions with Detroit.