Redd underwent surgery in March to repair a torn anterior cruciate ligament, and he left Saturday night's game against Detroit during the third quarter because of discomfort in the knee. He underwent an MRI on the knee on Sunday.
He said Tuesday the injury is "nothing totally too severe" and there's no connection between this and the season-ending one he suffered last Jan. 24, when he tore the anterior cruciate and medial collateral ligaments in the same knee.
The former All-Star accompanied the Bucks to Chicago for Tuesday's game and was to be examined by Bulls physician Dr. Brian Cole, who operated on him last March.
The nine-year veteran scored only 26 points in Milwaukee's first two games, shooting a combined 8-of-25 (32 percent). Carlos Delfino and Charlie Bell are expected to see an increase in minutes during Redd's absence.
The 30-year-old Redd signed a maximum deal after the 2004-05 season, but has struggled staying healthy since, missing 90 games over the last four seasons, primarily related to his left knee.
He has a player option for $18.3 million in 2010-11.
With Redd out, rookie Jodie Meeks was active for the first time.
Chris Sheridan is an ESPN.com NBA Insider. Information from The Associated Press was used in this report.