Davis, 28, was batting .196 with 26 home runs and 72 RBIs this season. He has hit 156 home runs and recorded 432 RBIs over six-plus seasons. Davis would be able to return in the postseason.
In a statement, Davis admitted to using Adderall and claimed he had permission to use it in the past. He also apologized to the team and fans.
Davis hit 53 home runs and drove in 138 RBI last year, the best of his career.
The Orioles, who have already lost catcher Matt Wieters and third baseman Manny Machado to injuries, are currently in first place in the American League East, at 86-59. The team opens a four-game series with New York in Baltimore on Friday.
- Chris Johnson