The Toronto Blue Jays are set to lose a key piece of their coaching staff. The Blue Jays later confirmed his departure via social media. Why is Mattingly leaving the Blue Jays? Mattingly's contract expired after the 2025 season, and "felt it was mission accomplished with the Blue Jays," according to one of Heyman's sources. Before his coaching career, Mattingly was a fan favourite among the rival Yankees, playing his whole career in the Bronx from 1982 to 1995.