Blue Jays right-hander Shaun Marcum could miss his next scheduled start with a blister. Marcum developed a blister on the middle finger of his pitching hand during his outing against the Orioles on Sunday. "We don't know," Blue Jays manager Cito Gaston said. "At this point in time, we don't know. Maybe we'll know a little bit more tomorrow, but I'm not sure."