LUCKLESS Collingwood defender Ben Sinclair will need surgery to repair the hamstring tendon he tore in Thursday night's win over Essendon.
The defender pulled up short after chasing down Bombers' forward Orazio Fantasia to lay a tackle in the third quarter.
He immediately left the ground and had scans on Friday morning to assess the damage.
The Magpies have not been able to put a timeline on his return, with football manager Geoff Walsh saying the timing of the surgery was yet to be determined.
"Scans have confirmed Ben has suffered a reasonably serious tear," Walsh told collingwoodfc.com.au
"Surgery, probably sometime next week, seems likely but the precise details of when that might be and how long his recovery might take won't be known until he has seen the surgeon."
North Melbourne defender Luke McDonald missed 10 week after surgery on his left hamstring last season although it remains unclear as to what lies ahead of Sinclair.
Sinclair, 25, has had little luck throughout his career to date, having played just 63 games since making his debut in 2011.
It was his first game back since he ruled himself out of the last five games of 2016 because of a series of concussions during the season.
Collingwood coach Nathan Buckley had praised Sinclair in a pre-season interview with AFL.com.au describing him "as courageous as there is going around."
The coach hoped he might have the chance to put together an uninterrupted season given his strong form at the start of 2016.
"The football he has been able to play when fit has been a pretty strong indicator for him and us and the fans as to what he is capable of," Buckley said.