Keuchel's contract was selected from Triple-A Round Rock on Saturday.
Keuchel will make his Rangers debut as the starter for Saturday's game against the Tigers, marking the third team he's pitched for at the major-league level this season. Even if he makes at least one more turn through the rotation while Cole Ragans (calf) is sidelined, Keuchel has posted a lackluster 8.53 ERA and 2.03 WHIP in 50.2 innings over 12 starts in the big leagues this year.