McGuire signed a minor-league deal with the Blue Jays on Thursday.
McGuire appeared in six big-league games with the Reds last season, allowing four earned runs off 10 hits and two walks while striking out 11 in 13.2 innings out of the bullpen. He spent a majority of the year with Double-A Pensacola, and will likely begin the 2018 season in the minors while serving as organizational depth for the Blue Jays, although he did earn an invite to spring training with the club.