The O’s then optioned Thames, who is recovering from a broken bone in his left hand, to Triple-A Norfolk.
Kelly, meanwhile, will head to Triple-A Tacoma.
In 57 games with Tacoma this season, Thames was batting .295 with seven home runs and 33 RBIs. The 26-year-old boasts a career .250 batting with 21 home runs and 62 RBIs in 181 Major League game with the Toronto Blue Jays and Mariners.
Also on Sunday, the Orioles activated Brian Roberts from the 60-day DL and designated pitcher Jair Jurrjens for assignment.
Roberts, 35, will be the designated hitter in Sunday night’s game against the New York Yankees. He will bat ninth.