The Chicago Bears have added a quarterback to the roster, but it's not Kyle Orton.  The Bears announced they have signed Josh McCown as a backup to Caleb Hanie.  Hanie was thrust into the starting role when Jay Cutler suffered a broken thumb Sunday against the Chargers.  Cutler underwent surgery on Wednesday and will begin rehab in a couple of days.  The Bears are hopeful he could return near the tail end of the regular season.  Chicago had put in a waiver claim for veteran Kyle Orton, who was released by the Broncos on Tuesday, but he was picked up by the Chiefs instead.  McCown spent 2010 playing in the United Football League.  He's appeared in 47 NFL games, including 31 starts, with the Cardinals, Lions, Raiders and Panthers.  McCown signed with the 49ers in August, but was later released.