When Guerrero fielded Christian Yelich's leadoff grounder in the fifth, the ball got stuck in the webbing of his glove. Guerrero removed the glove and flipped it to pitcher Trevor Richards to get the out.
The Brewers got the win, however, beating the Blue Jays 4-2.
Guerrero won the American League Gold Glove award at first base last season.
It's not the first time Guerrero has had issues with his glove. He had two throws go through his webbing last season, including one that led to a run for Seattle in a 6-5 loss to the Mariners in July.
The Associated Press contributed to this report.