Ben Roethlisberger sits out practice

PITTSBURGH -- Pittsburgh quarterback Ben Roethlisberger sat out Thursday's practice to rest his sprained left ankle and will be a game-time decision when the Steelers face St. Louis on Saturday.

Offensive coordinator Bruce Arians said the team will wait as long as possible before determining whether Roethlisberger or veteran backup Charlie Batch will start.

Roethlisberger passed for 330 yards but also turned over the ball four times in a 20-3 loss to San Francisco on Monday night. The quarterback said Wednesday he came out of the game better than he anticipated, but Arians said the long cross-country plane trip back aggravated swelling in the ankle.

Arians is working on two game plans depending on who starts. He said center Maurkice Pouncey (sprained left ankle) is also a game-time decision.