12/23/2011 03:17 EST | Updated 02/22/2012 05:12 EST

Ben Roethlisberger out with ankle injury, Batch to start against Rams

PITTSBURGH, Pa. - Pittsburgh quarterback Ben Roethlisberger won't start Saturday when the Steelers face the St. Louis Rams.

Roethlisberger is dealing with a sprained left ankle and did not practise this week following a 20-3 loss to San Francisco on Monday. He will be replaced by veteran Charlie Batch, who is 4-2 as a spot starter since joining the Steelers in 2003.

Roethlisberger said Wednesday he would prefer to play and believed his ankle was in pretty good shape after throwing for 330 yards and three interceptions against the 49ers. Yet he watched both practices this week in sweat pants as Batch took the snaps with the first team.

Roethlisberger last missed a start due to injury in 2009 when a concussion forced him to sit out a loss to Baltimore.