St George Illawarra coach Paul McGregor insists form will dictate who will finish the year in the number one jumper when Euan Aitken returns from a shoulder injury in a fortnight.

McGregor this week opted to push star Josh Dugan to the centres after Aitken’s injury, keeping rookie Matt Dufty at fullback for Saturday’s NRL clash against Newcastle.

“He’s working hard with his injury, when he does get back on the field, we’ll make a decision there and it’ll be mainly on form then,” McGregor said of Aitken on Friday.