Tomlin told reporters Tuesday that Roethlisberger had a successful throwing session on Monday and has improved in his physical condition from a week ago. Roethlisberger has been inactive the past three weeks with a rib and shoulder injury.
"We'll see what it looks like on a football field (Wednesday)," Tomlin said. "He'll be given an opportunity to prove that he is healthy and we'll kind of let that process go from there. In the meanwhile, obviously, Charlie (Batch) is our guy and we'll prepare and plan with that in mind."
Tomlin said that Wednesday's practice will "provide some clarity" on the quarterback situation. Tomlin said Byron Leftwich is recovering as well, but Roethlisberger's practice reps will come at Leftwich's expense this week.
The Pittsburgh Post-Gazette reported earlier Tuesday that the Steelers expected Roethlisberger to play Sunday against the San Diego Chargers. Tomlin wasn't nearly as definitive, but Wednesday's practice could bring the picture into focus.
Follow Dan Hanzus on Twitter @DanHanzus.