Chicago Bears' running back Cedric Benson hurt his left ankle at the end of a 21-yard run early in the second quarter of Sunday's game against the Denver Broncos and had to leave the field on a cart. He did not return. Coach Lovie Smith said after the game Benson had an ankle injury but did not elaborate on his condition. Benson carried eight times for 47 yards. "Whenever you don't finish the game, of course, that's not good," Smith said. "He has a pretty good ankle injury." Benson, who took over this season as the Bears' starting tailback after the trade of Thomas Jones, broke free for the long run but was hurt as he landed while being tackled by Denver safety Hamza Abdullah. Benson lost the ball on the play, but officials ruled he was already down before it came loose.