If Gibson is out then he'd most likely play Fellaini-Osman as the midfield two, but i seriously wouldnt up against playing this;
Howard
Stones Jagielka Distin
Coleman Fellaini Barkley Baines
Mirallas Jelavic Pienaar
OR
Howard
Stones Jagielka Distin
Coleman Fellaini Barkley Baines
Pienaar
Jelavic Mirallas
Its something a little less predictable and being honest, we've havent looked too bad as a 3 back in Pre-Season.
Barkley gives the ball away too much in the wrong areas of the pitch.....he needs to be higher up the pitch.