With Donaldson sidelined, Ryan Goins was starting at third and batting ninth. Donaldson left Sunday's loss at Tampa Bay with a sore right calf, the same injury the 2015 AL MVP had in spring training.
Manager John Gibbons said: "It's still hanging around. We'll see where he's at tomorrow. He's a big piece, obviously."
Donaldson, who is batting .348 with two homers and three RBIs, said he was disappointed not to start the home opener but understood the team's decision.
"They wanted to take a little bit more of a cautious route than I wanted to take," Donaldson said. "I don't really take much pleasure in thinking of the long haul. I would rather play today and see what happens tomorrow."
General manager Ross Atkins said he doesn't expect Donaldson to be sidelined for long.
"We're optimistic he'll have this turned around in a hurry," Atkins said. "I think he could be playing as early as tomorrow."
If Donaldson needs to DH for a day, Gibbons said Kendrys Morales would play first base.
The last-place Blue Jays are 1-5, matching their worst start through six games. Toronto's slugging percentage is .297, the lowest in the AL.
Toronto optioned right-hander Casey Lawrence to Triple-A to make room for Osuna.