The Athletics claimed Thomas off waivers from Atlanta on Thursday.
Atlanta optioned Thomas to Triple-A and later waived him after he gave up 11 runs in just 2.2 innings during his last big-league appearance Monday. The A's will bring him in despite his poor performance, though it's unclear whether he'll immediately claim a spot in the big-league bullpen. Mark Leiter (hip) was transferred to the 60-day IL in a corresponding move.