Remove pot roast; cool slightly. Skim fat from cooking liquid; reserve liquid. Trim and discard excess fat from cooked pot roast. Combine shredded pot roast and barbecue sauce in 3-quart saucepan. Cook over medium heat 8 to 10 minutes or until heated through, stirring frequently, adding enough reserved cooking liquid (up to 1/2 cup) to maintain a moist consistency, if necessary. Serve on rolls.