BRISBANE Lion Rhys Mathieson will miss up to six weeks after having surgery on his fractured face on Monday night.

Mathieson received the injury following a high bump from Jeremy Cameron that cost the GWS forward a four-game suspension after he pleaded guilty to rough conduct at the Tribunal on Tuesday afternoon.

Lions' head of physiotherapy Shane Lemcke told the club's website Mathieson had two fractures – one to his cheekbone and one to the bone below it - to the right side of his face.

He said the teenager would miss four to six weeks.

Second-year forward Jaden McGrath was injured in the same NAB Challenge match on Sunday, but was cleared of a fracture in his left shoulder.

"He injured his left centre clavicular joint," Lemcke said.

"Fortunately he didn't fracture his clavicle but he’s still going to be out for a couple of weeks."

Forward Josh Green (foot) and captain Tom Rockliff (hamstring) will rejoin the main playing group on Thursday when the Lions return from a three-day break.

Rockliff has declared himself a certainty for round one.