Toronto selected the contracts of right-handers Shawn Hill and Bobby Korecky before Monday's doubleheader that opened the four-game series at Camden Yards. The Blue Jays then shifted pitcher JA Happ to the 60-day disabled list.
"We've got four games in 72 hours," Blue Jays manager John Farrell said. "We've had a few short starts of late, and to protect against short starts over the next three days, we've added arms."
The Blue Jays played the doubleheader Monday followed by single games on Tuesday and Wednesday. They have no off-days until the season ends next Wednesday.
Hill was 9-2 with a 4.51 ERA pitching for Triple-A Las Vegas but has never pitched in relief in the Major Leagues. He's made 44 starts.
Korecky also comes to the Blue Jays from Las Vegas, where he posted a 3-4 record with a 3.44 ERA. He's pitched 21 times in the Majors, all in relief.