Grayson has reverted to a 3-5-2 formation with wing backs on Pretson's return to the Championship. He employed the formation previousl at times in League One but in Cup games against higher level oposition.
Preston kept a clean sheet at Rotherham on Tuesday after a goalless draw although Bailey Wright came closes to breaking the deadlock by hitting the bar.
A home game against early pacesetters Ipswich awaits Preston on Saturday where North End will hope to keep their unbeaten start to the season going.