Luckless ruckman Braydon Preuss will undergo surgery after injuring his right pectoral muscle.

Preuss, who was set to return to the field this week from a left shoulder reconstruction, suffered the injury in the gym on Tuesday.

The injury is on the opposite side to his shoulder injury from earlier this season and is unrelated to the previous injury.

GIANTS Head of Medical Cullan Ball said Preuss will see a specialist on Wednesday.

“It’s shocking luck for Braydon who was on the cusp of returning from his shoulder injury,” Ball said.

“Scans on Tuesday afternoon revealed he’s torn his right pec muscle and he’ll consult a specialist on Wednesday.

“We expect he’ll undergo surgery and is likely to be sidelined for three-to-five months.”