Bell (Achilles) participated in Thursday's practice, Dave Birkett of the Detroit Free Press reports. Bell's activity level was unclear, but more pressing is his potential availability Sunday in Green Bay. On Thursday, coach Jim Caldwell wouldn't confirm or deny that Bell is in danger of sitting out in Week 17, only telling MLive.com, "We'll see." Prior to developing the injured Achilles, Bell reached the end zone four times in as many games, which he supplemented with 310 yards on 69 carries and 120 yards on 13 catches. If he's deemed inactive in the season finale, Reggie Bush would assume top billing out of the Lions' backfield, with Theo Riddick and George Winn acting in complementary roles.