The 28-year-old had a light game of catch Friday afternoon, but manager John Gibbons was not exactly optimistic that Morrow would be ready by Sunday.
"Morrow is up in the air for Sunday," Gibbons said. "He's feeling a little bit better, but two days away, I don't know. I haven't had a chance to talk to the trainers and the pitching coach just yet, but it's dicey."
Morrow allowed four runs while striking out two during his last start. He managed to get his fastball above 90 mph to just one hitter during that outing and was clearly not himself on the mound.
If Morrow misses the coming outing, it is not immediately clear who would take his place. Right-hander Esmil Rogers was ruled out for the job after he threw more than 60 pitches on Wednesday, and Gibbons does not want to bring him back on short rest. The same situation applies to Marcus Stroman, ranked the Blue Jays' No. 5 prospect by MLB.com, who also pitched on Wednesday for Double-A New Hampshire.
Right-hander Justin Germano is scheduled to start for Triple-A Buffalo on Sunday and could enter the mix. Gibbons mentioned right-handed reliever Todd Redmond as a possibility while Ramon Ortiz could become a possibility if Morrow heads to the disabled list.
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.