The Tigers selected Rainey's contract from Triple-A Toledo on Tuesday.
Rainey will make his first appearance in the big leagues this season after having his contract selected by Detroit on Tuesday. The 32-year-old has posted a 5-3 record, 2.32 ERA, 1.28 WHIP and 60:26 K:BB through 42.2 innings at Triple-A Toledo this season. Rainey's promotion comes in the wake of Enmanuel De Jesus heading out on paternity leave.