"He's a good pitcher for us. Hopefully it won't be too long but you never know," said Jays manager John Gibbons. "He'll be checked out. There's a lot of wear and tear on that arm, you know."
The 42-year-old Oliver made his debut 20 years ago for Texas. He went on to play for St. Louis, Boston, Colorado, the Mets, Angels and Texas two more times before becoming a Jay in 2012.
The reliable left-hander has appeared in 17 games this season posting a 2-1 record with a 3.18 ERA, largely in his role as the team's eighth-inning man.
The move to the DL is retroactive to May 19. Doctors are waiting to see how Oliver responds to a cortisone shot to the shoulder. An MRI is also expected.
Oliver joins pitchers Kyle Drabek, J.A. Happ, Drew Hutchison, Josh Johnson, Dustin McGowan, Luis Perez and Sergio Santos on the Jays' disabled list. With Ricky Romero also out of the picture — he's down in the minors, trying to rediscover his form — Toronto has been struggling to fill holes in its starting rotation.
In the spring, the Jays anticipated a blue-chip rotation featuring reigning NL Cy Young-winner R.A. Dickey, Brandon Morrow, Mark Buehrle, Johnson and Romero — some US$46.75 million of prime pitching beef.
Toronto's starting pitchers were expected to be a well-oiled machine, mowing down opposition batters.
Instead, Toronto was forced to use double-A pitcher Sean Nolin to fill a void against the Baltimore Orioles on Friday night. The 23-year-old left-hander is 2-0 with a 1.17 ERA in three starts with double-A New Hampshire this season.
He becomes the 10th Jays starter this season, joining the original five-man rotation, Happ, Aaron Laffey, Chad Jenkins and Ramon Ortiz.
Johnson is in the minors, working his way back from time off due to soreness in his right triceps muscle.
Drabek and Hutchison are both recovering from 2012 Tommy John surgery. McGowan is looking to return from a string of shoulder injuries while Perez suffered a torn ulnar collateral ligament in his left elbow last season.
Happ has been shifted to the 60-day disabled list as he recovers from injuries after taking a ball in the head during a game earlier this month. He hurt his knee in falling after being felled by the pitch.
"He's just waiting for the knee to recover enough where he can start doing some things," said Gibbons. "His head's fine, though."
Santos has been sidelined by an elbow issue. Closer Casey Janssen is getting the job done while managing his shoulder, which was operated on in the off-season.
The good news for Toronto is that the marquee starters that are healthy are finding their rhythm. Dickey, Morrow and Buehrle have all delivered quality starts of late. Plus Toronto's bats have come alive, helping the Jays win seven of their last 10 ahead of Friday.
Still as a unit, Toronto's starters were 11-18 this season going into Friday night play while the bullpen was 9-9.
While Oliver will be missed, the Jays have got good performances out of fellow lefties Brett Cecil and Aaron Loup.
Oliver will be watching from the sidelines while waiting to see how his shoulder responds to rest. He said it made no sense trying to pitch through the problem.
"At this stage of my career, if I can't go out there and pitch the way I want to, I'm going to go ahead and be smart," he said.