"I'm not going to try to throw 110 [mph]," Fernandez said. "Got to keep in mind that I'm still rehabbing. I'm not going to be throwing 100 percent. But I'll be letting it go."
Marlins manager Mike Redmond said Thursday's session will be "just another step in the process to his recovery" and that physically Fernandez is ready to go.
"I'm sure it will be an exciting day for him to face some hitters and kind of get that adrenaline going a little bit," Redmond said Wednesday before the game against the Mets at Marlins Park.
Fernandez would not speculate when he might be ready to rejoin the Marlins.
"Everything depends on [Thursday] and three days after that. That's the approach that I'm taking," Fernandez said. "I don't want to go crazy and start thinking about a day because it's going to change. I don't want to disappoint myself. ... I feel fantastic. Knocking on wood right now. I feel like I haven't left the game. I do what my doctor says. I've just got to follow a plan, follow the rules the way that I have to."