"It's going to be awhile," General Manager
Mozeliak called the injury a significant tear but would have more information after the results of an MRI exam are reviewed by doctors.
Adams was injured running out a double in the fifth inning Tuesday night against Arizona. He is batting .243 with four home runs and 20 runs batted in.
Baltimore Orioles outfielder Alejandro De Aza was designated for assignment.
De Aza, 31, batted .214 with three home runs and seven RBIs in 30 games. De Aza has a $5-million contract this year after losing an arbitration hearing with the Orioles.
Also, the Orioles announced the signing of Cuban left-hander Ariel Miranda to a minor league contract.