The Bucks announced Thursday that Lopez had back surgery earlier that day in Los Angeles. Team officials didn't provide a timetable for his eventual return.
Lopez played 28 minutes and had eight points, five rebounds and three blocks in a season-opening victory over the Brooklyn Nets, but he hasn't played since.
Brook Lopez underwent successful back surgery today in Los Angeles.
Lopez will continue to be listed as out and updates on his rehabilitation progress will be provided as appropriate.https://t.co/QyZkiNLAKb
— Milwaukee Bucks (@Bucks) December 2, 2021
The Bucks (14-8) have missed the seven-footer's size, rebounding and shooting, which have been a mainstay on the team for much of the past three seasons. The 33-year-old is in his fourth season with the Bucks and 14th season overall.
He averaged 12.3 points, 5.0 rebounds and 1.5 blocks last season while helping the Bucks win the NBA title.
Bucks officials said Robert Watkins performed the surgery, with oversight from team doctor William Raasch.
Bobby Portis has been filling Lopez's spot in the starting lineup and has averaged 15.1 points and 8.3 rebounds. Milwaukee has signed free agent DeMarcus Cousins to add depth to centre.
The Bucks take on the Raptors (9-13) on Thursday night.
--with files from The Associated Press