Headland, 29, will be placed on the club’s long-term injury list, and football manager Chris Bond said the club expects he will be available for selection again by round 15.
It’s the third time in as many campaigns that Headland's season has been curtailed by injury, after a string of knee, quad, stress fracture and hamstring injuries restricted him to 15 games from 2008-2009.
After a pre-season hamstring scare, Headland played the first four games of the season before being left out of the side’s round five clash with Richmond with what appeared to be a two-week knee injury.
His placement on the long-term injury list means rookie Alex Silvagni can stay in the side as Antoni Grover prepares to return from his own knee injury via the WAFL.
Headland, who accepted a one-year contract extension for 2010, said this pre-season that he would consider his football future at the end of the year and his body would dictate whether he plays on.
"I just want to make sure this year I give it everything I can to play real good footy," he said at the time. "If that happens and I play some good footy I'm sure I can go on again.
"It all depends on injury and my body at the end of next year.”
