Gibaut had been on the injured list since April 26 with a right shoulder impingement. He made four rehab appearances with Louisville and did not allow a run in four innings. He threw a scoreless inning Sunday in his last appearance.
Gibaut made 12 appearances for the Reds before going on the injured list. He had a 5.40 ERA in 11 2/3 innings.
Gibaut was the losing pitcher on Opening Day on March 27, giving up four earned runs in the ninth inning in a 6-4 loss to the San Francisco Giants at Great American Ball Park.
The Reds (25-25) return to action at 12:35 p.m. Wednesday in the final game of a three-game series against the Pirates (16-33).
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