But neither absence should bring up a cause for concern, and all three could be available to pinch-hit.
Baker (swollen left eye) and Cantu (dizziness) were planned off-days, and with a quick turnaround from Wednesday night's 13-4 loss to the Cardinals, manager Fredi Gonzalez decided to give Ramirez an off-day to rest his bothersome right groin and back.
Gonzalez and Ramirez have said the Dominican slugger is going to be playing through pain in that groin -- which he suffered while beating out a grounder against the Phillies on May 26 -- all year.
On Wednesday, Ramirez was in noticeable pain when he grounded into a fielder's choice in the fourth inning and was later hunched over while being spoken to by third-base coach Bo Porter.
But Ramirez said the groin isn't in any more pain than it was before, and that he was just tired upon reaching third base.
"He's played  in a row, and he's been banged up with that groin," Gonzalez said. "When your legs are not all right, your body tends to overcompensate. [On Wednesday], he had a little problem with his back, and you saw it running the bases there that one inning.
"There was some question as to whether he was going to be able to get through that game or not, but he did."
Gonzalez said Ramirez and Cantu should be back in the starting lineup against the Blue Jays when the two clubs begin an Interleague series on Friday. Cantu will likely serve as the designated hitter that game, with lefty bat Ross Gload starting at first base against right-hander Roy Halladay.
Baker, who has no blurred vision in the eye, said he expects to be back behind the plate on Friday, too.
Taking the place of the injured starters on Thursday were Wes Helms (batting third and playing third base), Gload (playing first and batting sixth) and Ronny Paulino (catching and hitting eighth).
Alden Gonzalez is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.