Cueto returned to Cincinnati on Saturday to be examined after leaving the series opener at Texas on Friday night because of tightness in his right lat muscle.
Right-hander Logan Ondrusek had joined the Reds in Texas from Triple-A Louisville.
Cueto, the Reds' opening-day starter, was on the DL from April 15 to May 19 with a strained right lat. He missed the first half of June with what was called a strained right shoulder, though it was related to the problem in his upper back.
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