Red Sox manager Bobby Valentine, Ortiz and the medical staff waited until after batting practice to decide whether the slugger would be activated from the disabled list.
"If he gets the clearance, he'll be in the lineup and then we'll make a corresponding roster move," Valentine said before batting practice.
To make room on the roster, the Red Sox optioned right-handed reliever Junichi Tazawa to Triple-A Pawtucket.
Ortiz has been on the DL since July 17 with a right Achilles strain.
"I thought the craziest thing with David is it didn't initially seem like it was going to be very long," Valentine said. "So with each passing day, I think the disappointment was a little more that we didn't have him."
With Ortiz out 35 games, the Red Sox went 13-22.
"He wants to be out there more than anybody," Red Sox outfielder Cody Ross said. "He's trying everything he can to do everything he can without putting his season at risk, or even next season, because you know you're talking about a foot and you don't mess around with that.
"You're always on it, you need it to swing, to run, to do everything. He's smart enough to know that, and he wanted to come back as fast as he could, and I would assume today is the day that he thought this was as soon as possible."
Ortiz is not 100 percent and won't be until he's able to rest it at length during the offseason. He said Thursday he'd be able to play with how he feels.
"Fifty percent of David Ortiz is better than no David," Ross said. "But at the same time we want him to be healthy and we want him to be him and productive. He wants that for himself, too. It's going to be nice to get him back in that lineup."