Juventus centre-back Bremer will undergo surgery after sustaining an anterior cruciate ligament (ACL) injury against RB Leipzig.
The Brazil international was forced off six minutes into Juve's 3-2 win over Leipzig on Wednesday, with the club confirming the extent of his injury on Thursday.
Bremer has been key to Thiago Motta's side so far this season, playing every minute in Serie A with the team yet to concede a single goal in six matches.
Among his team-mates, he has played the most minutes (540), making the most interceptions (six) and blocks (11).
Juventus were also dealt another blow, with midfielder Nico Gonzalez suffering a thigh muscle injury.
"Bremer and Nico Gonzalez underwent diagnostic tests which revealed an anterior cruciate ligament injury in the left knee for the former and a low-grade injury to the rectus femoris of the right thigh for the latter," the club said in a statement.
"Bremer will undergo surgery in the coming days."