Scans today have confirmed that key West Coast Eagles defender Eric Mackenzie ruptured his right anterior cruciate ligament in the game against Carlton at Rushton Park last night.



Mackenzie, the 2014 John Worsfold medallist, landed awkwardly after a contest in the second quarter and hobbled from the ground.



He will wait for swelling in the knee to subside this week before having surgery.



Mackenzie has played 71 of the last 75 games the club has played and in that time, has emerged as one of the premier key defenders in the game.



He was unlucky to miss all-Australian selection last year and edged out Brownlow medallist Matt Priddis for the club best and fairest award.



The 26-year-old Mackenzie, who was one of the senior players rotated through the captaincy last season, has played 121 games and has been rock solid down back.