One day after that six-inning outing against the Brewers, the Blue Jays placed Marcum on the 15-day disabled list. Toronto's medical staff determined that he was suffering from strained ligaments around his elbow and forearm, an assessment later confirmed by arm specialist Dr. James Andrews.
Marcum isn't entirely sure what caused the discomfort, which had affected the 26-year-old for a few starts before he was shelved. To hopefully avoid a similar problem in the future, the pitcher plans to focus his workouts on strengthening the muscles around his elbow.
"I have no idea [what caused the pain]," said Marcum. "It could be because I have been throwing a lot of cutters -- a lot more this year than I have in the past.
"Every time I threw, it almost felt like somebody was flicking my funny bone. That's gone, too, so that's good."
The cut fastball has been an important pitch this season for Marcum, who is 5-4 with a 2.65 ERA in 15 starts for the Jays this year. And with opponents hitting just .198 against him, he said he doesn't plan on abandoning the pitch. The pain didn't resurface in his recent Minor League rehab outing.
On Thursday, Marcum took the mound for Class A Dunedin and turned in four perfect innings against Vero Beach, striking out six. Marcum threw 55 pitches and will be limited to 65-70 if he starts against the Orioles on Tuesday.
"My arm felt great," Marcum said. "It was A-ball, so I got away with some pitches that probably would've been hit a long way up here. But I wasn't really worried about that. I just wanted to go out there and make sure everything was healthy.
"It's not too much fun rehabbing. It's the first time on the DL for me and I never want to be there again, that's for sure."
Taking the hill on a strict pitch limit, however, isn't unfamiliar for Marcum. Last season, the Jays moved him from the bullpen to the rotation on May 13 and allowed him roughly 70 pitches. Marcum went on to spin six no-hit innings against Tampa Bay before being pulled from the contest.
"I was fortunate," Marcum said with a smile. "They were swinging early in the count. Hopefully, Baltimore will do the same thing and not go up there and take pitches, knowing that I have the pitch count."