In a corresponding move, Toronto designated pitcher Carlos Ramirez for assignment.
Gurriel, 24, has only hit .206/.229/.309 in 70 plate appearances in his first taste of Major League action in his career.
McGuire, who signed a minor league contract with the Blue Jays back in November after spending last season in the Cincinnati Reds organization, sports a 2.70 ERA with 27 strikeouts and 12 walks in 30 innings pitched with Buffalo this season.
The 28-year-old has only pitched 13.2 innings in the Majors, making his big league debut last season while with the Reds.
Toronto concludes its weekend series with the Boston Red Sox Sunday afternoon.