Ben Roethlisberger (ankle) improving

Ben Roethlisberger's chances of playing in Pittsburgh's game against San Francisco on Monday night seem to be improving by the day.

"I'm optimistic," Steelers coach Mike Tomlin told ESPN event news editor Jim Carr on Sunday. "If he's healthy enough to play, he'll play."

According to the Pittsburgh Post-Gazette, Roethlisberger is expected to start. The newspaper reported the decision was made before the division-rival Ravens' 34-14 loss to the Chargers on Sunday night.

If the Steelers defeat the 49ers they will move to 11-3 on the season hold a one-game lead in the AFC North over the Ravens (10-4).

Roethlisberger was limited Friday in his first practice since spraining his left ankle during a 14-3 win over Cleveland on Dec. 8. He practiced again Saturday, with guard Ramon Foster saying the quarterback showed little problems throwing the ball despite limited mobility.

"His ankle was better than it was last Thursday (when he injured it)," Tomlin told Carr, adding that Roethlisberger "looked good" in Saturday's practice.

Tomlin said he likely won't make a decision until pregame warm-ups, in order to evaluate Roethlisberger's ability to move in the pocket.

Roethlisberger last missed a start due to injury in 2009. Veteran Charlie Batch will get the start if Roethlisberger can't go against the 49ers.

"Ben's competitive," Tomlin told Carr. "Something like this stokes his fire. He loves a little adversity. But we won't be negligent. We'll see how it unfolds."

Information from The Associated Press contributed to this report.