The Blue Jays could turn to one of their veteran arms from Triple-A Buffalo, but there's also a strong likelihood that prospects Marcus Stroman and Sean Nolin -- ranked third and fifth, respectively -- will receive consideration.
"We're not sure which way we're going to go, to be honest with you," Blue Jays manager John Gibbons said.
Nolin, who was recently promoted to Buffalo, might be the early favorite. The lefty, taken in the sixth round of the 2010 First-Year Player Draft, allowed two runs over 5 1/3 innings during his first start for the Bisons and would need to have his next scheduled outing pushed back only one day in order to make that appearance for Toronto.
The 23-year-old Nolin is 8-4 with a 3.03 ERA in 98 innings for Double-A New Hampshire and Triple-A. He made a brief appearance for the Blue Jays earlier this season, allowing six runs over 1 1/3 innings.
Since the Blue Jays have already used one of Nolin's options this season, he would be the likely choice if the club is looking for just a spot start. But the lefty is also receiving stiff competition from Stroman, who was taken with Toronto's first-round Draft pick in 2012 and is still with New Hampshire. He appears ready for a shot in the big leagues, however.
Stroman is 8-4 with a 3.22 ERA for the Fisher Cats this season. The right-hander has struck out 109 batters in 95 innings, and he would be pitching on two additional days of rest if he got the call for Saturday's game.
Right-handers Kyle Drabek and Drew Hutchison also could receive some consideration, but they'll likely need more time while returning from Tommy John surgery. Both pitchers are expected to join the Blue Jays in September, and it's possible that starting jobs could be up for grabs if either Esmil Rogers or Todd Redmond is eventually pulled from the rotation.
Gregor Chisholm is a reporter for MLB.com. Read his blog, North of the Border, and follow him on Twitter @gregorMLB. This story was not subject to the approval of Major League Baseball or its clubs.