The Chicago Bears biggest area of concern for the upcoming season is the offensive line.  Sources close to the situation say veteran lineman Chris Williams will move back to the offensive tackle position.  Williams, the Bears' 14th overall pick in 2008, was drafted to play left tackle.  He hasn't started a game at tackle since Week Two of the 2010 season.  Williams started at guard last season before a dislocated wrist landed him on the injured list.