PITTSBURGH — Willie Parker is back on the Pittsburgh Steelers' injury list.

Parker missed practice for the second day in a row Thursday because of a shoulder injury — not the sprained knee that kept him out of four games — and the running back's status for Sunday's game against Indianapolis is uncertain. The Steelers' final practice of the week is today.

Ben Roethlisberger, dealing with a slightly separated right shoulder and a left pinkie ligament injury, also didn't practice Thursday. The Steelers quarterback is optimistic about practicing today and playing against the Colts, although he sat out the second half of the Washington game Monday.