Greater Western Sydney power forward Jonathon Patton has suffered a knee injury and been helped off the field in his side’s AFL clash with St Kilda at Manuka Oval.

Patton screamed in pain when he was tackled into the turf by Saint Rhys Stanley midway through the second term.

The 2011 No.1 draft pick immediately clutched his right leg and was unable to stand up.

He was carried off the field and down the race by two GWS officials shortly before halftime in Saturday’s match in Canberra.

The Saints held a 37-point lead at the major break.

St Kilda were forced to active their substitute Farren Ray early in the second quarter, with Jack Newnes (concussion) given the red vest.