Notice how the LBs have full view of both Davis and Griffin?
At this exact moment in time Davis is not 'wide open' because there are 2 defenders looking at Davis and Griffin:
Notice that Griffin is already set to throw/already begun his throwing motion with the ball cocked back its only then that the LBs begin slough off Davis and react to the ball in flight:
By the time the ball is in the air the linebackers have already negun to slough off.
By the time the ball reaches Moss, of course Davis
appears wide open.