Stuttgart striker Cacau ruled out for at least three months
The 31-year-old was preparing for Stuttgart's home game against Hamburg on Sunday when the injury to his knee occurred.
Cacau will now receive conservative treatment and wear a special splint as doctors try to avoid having to resort to surgery.
Fredi Bobic, Stuttgart’s director of sport, said. "This is bitter for us. I'm dreadfully sorry for him.
"We will support him in every possible way and hope he can spare himself surgery which would see him sidelined for even longer."
Cacau has played five Bundesliga games for Stuttgart this season, scoring one goal in his side’s 2-2 draw in Bremen.
The club has won only one of seven games this season and are 15th in the 18-team top division.
Brazilian-born Cacau, who moved to Stuttgart in 2003, has won 23 caps for Germany but was not selected for their Euro 2012 squad and has not been called up to the team ever since.