Because Bulaga broke last time they put him at LT and they don't want to screw around with the unit that will keep Rodgers healthy and thus be the key to the Packers offensive success this year. Bulaga plays his two series at RT and then goes to the bench. Barclay gets to go out to LT and get beaten like a gong until he either gets his feet under himself and his mind right or loses whatever confidence he has left.