St George Illawarra coach Paul McGregor has confirmed he'll switch Josh Dugan back to fullback after next month's final State of Origin clash.

McGregor's first move when he took over from Steve Price last month was to shift Dugan to right centre for the first time in his NRL career - the role he then filled for NSW in game two.

However, with Dylan Farrell edging towards a return to action against North Queensland next week after tearing his pectoral muscle in round six, McGregor expects to restore Dugan to his favoured position after Origin three on July 9.

"Dylan Farrell is back either next week or the week after and he's the only genuine right-sided centre at the club," McGregor said.

"Dylan was brought here to play first grade, Duges was brought here to play first grade ... but it's the best fit for the team at the moment to have Duges on that right edge and he's done well there.