McGuire's contract was selected from Double-A Pensacola on Tuesday, Zach Buchanan of the Cincinnati Enquirer reports.
He will get a late-season reward for posting a 2.79 ERA, 1.08 WHIP and 170 strikeouts in 168 innings for the Blue Wahoos. While those are stellar numbers, this was a 28-year-old on a minor-league deal facing batters who were on average, four or five years younger than him. He will likely pitch in low-levarage situations out of the bullpen, but it's possible that he could receive a spot start or two.