BOSTON -- Right-hander Jason Frasor was placed on the 15-day disabled list on Saturday afternoon with tightness in his right forearm.
Frasor is optimistic that the injury will end up being a relatively short-term problem, but he's scheduled to undergo an MRI on Monday with Dr. James Andrews to rule out any further damage.
The soon-to-be 35-year-old has experienced soreness for most of the season, but he experienced a different level of pain while warming up in Boston on Friday night.
"I've had discomfort, I think we all have had discomfort, for a few months now," Frasor said. "But I never said anything, I drank my Red Bull and everything's fine. You add in adrenaline, and it's really not that big of a deal. I've almost gone four months now doing that exact routine.
"But last night was a little different ... a little tighter, a little more discomfort. I just didn't feel right."
Frasor is 1-1 with a 4.00 ERA, along with 45 strikeouts in 36 innings this season. His 42 appearances and 12 holds this year are both ranked first for Toronto.
The Chicago native is currently in his ninth season at the Major League level. He previously underwent two Tommy John surgeries in his career -- once in college and once while in the Minors -- but this is the first time he has been placed on the disabled list at the big league level.
"It is remarkable when you consider nine years of never being inactive and this is the first time over that nine-year period," Blue Jays manager John Farrell said. "A couple of things quickly come to mind. One, it's a tremendous work ethic to keep himself in shape.
"Two, he has a very clean delivery, a clean arm action that doesn't place undue stress on the shoulder or the elbow, and that's what has allowed him to have the longevity and the durability that he has shown."
The injury is yet another setback for a club that has been decimated by injuries for most of the past two months. Starting pitchers Brandon Morrow, Kyle Drabek and Drew Hutchison are on the disabled list, while relievers Sergio Santos and Luis Perez have been ruled out for the rest of the year.