To make room on the roster, hard-throwing righty Jeremy Jeffress was designated for assignment. The Blue Jays now have 10 days to trade, release or assign Jeffress, but he must clear waivers prior to being sent to the Minors.
"We needed someone who could chew up some innings," manager John Gibbons said. "Bush almost made the team out of Spring Training. He can do that for us. We're a little beat up. We're good to go today, but we've been a little beat up these first few days."
The writing was on the wall for Jeffress after he struggled to get through the ninth inning of Friday night's 6-4 loss to Boston. He surrendered a solo home run to the first batter he faced and then loaded the bases before escaping the 29-pitch inning without any further damage.
Jeffress, who was acquired in an offseason deal with the Royals, has an impressive arm with the ability to throw in the upper-90s, but so far he has been unable to master it in the Major Leagues.
The 25-year-old has averaged 7.3 walks per nine innings in 38 appearances at the big league level. If Jeffress is able to solve that problem, he could become a valuable reliever. Until that time comes, however, he's not someone that can be relied upon.
"It's kind of in and out with the consistency," Gibbons said. "Some days he's on, he throws a lot of strikes, and that's the key for him. If he ever harnesses that, he has a chance to be a good pitcher. If not, he'll be battling that until he gets it. But we definitely saw progress. It's just, right now at this point we need somebody."
Bush had been out of the Major Leagues since 2011 and spent last season pitching in South Korea. He signed a Minor League deal with Toronto during the offseason and was a late cut from the team in Spring Training.
The 33-year-old was originally drafted by the Blue Jays in 2002 and spent parts of two seasons with the club from 2004-05. He is expected to serve as the long reliever while Toronto carries an eight-man bullpen until Brett Lawrie is able to return from the disabled list later this month.
"I felt like I pitched well," Bush said of his spring. "My goal in camp was to show that I could still get guys out. I didn't have a whole lot of expectations beyond that, other than trying to pitch well and leave a good impression.
"I don't think I expected anything this quickly, but I felt like I put myself in the position that if there was an opportunity I would be ready for it."