Betemit was hurt Monday while running the bases in an exhibition game and had an MRI. He was diagnosed with a tear of the posterior cruciate ligament.
Betemit said Tuesday that he's glad he won't need surgery.
The 31-year-old Betemit hit .261 with 12 home runs and 40 RBIs last season with Baltimore. He played third base, first base and the outfield, and also was a designated hitter.
Betemit has played for Atlanta, the Dodgers, the Yankees, the White Sox, Kansas City and Detroit.