Lions cornerback Chris Houston and safety Louis Delmas are listed as doubtful for Sunday's game against the San Francisco 49ers. Lions rookie cornerback Bill Bentley has been ruled out for Sunday's game as he recovers from a concussion sustained this past Sunday against the St. Louis Rams. Lions defensive end Lawrence Jackson (calf) and Corey Williams (knee) are listed as questionable. Williams hasn't practiced all week, while Jackson was limited on Friday. Meanwhile, Lions receiver Calvin Johnson (foot) is probable for Sunday's game. Source: MLive.com