ERIC Mackenzie will have a traditional knee reconstruction next week as he begins the long road to recovery from a ruptured anterior cruciate ligament.

West Coast's reigning best-and-fairest ruptured the ACL in his right knee during the Eagles' 31-point win over Carlton in the NAB Challenge last Friday night.

The 26-year-old had to wait a few days until the swelling subsided in his knee before he and the Eagles' medical staff could make a decision on what type of surgery to have.

"We're going with a traditional knee reconstruction," Mackenzie told the club's website.

"So traditionally it's a 12-month recovery from that.

"Having spoken to Lecca (Mark LeCras) and Brownie (Mitch Brown), who've both had the traditional knee, they've both come back with no problems.

"So I think that’s the way to go."

Mackenzie said he initially thought he had copped a knock to the knee, when in reality his knee had buckled without contact.

It wasn't until the physio started to test his knee that he feared the worst.

"Immediately I just thought it was a knock on the knee, a bit of soreness that would go away pretty quickly," Mackenzie said.

"I managed to get up, and I started jogging off towards the end of it so I thought I'd be right to come back on.

"It's only when the physio started doing the tests – I know what the ACL test is – they weren't happy with the results so they took me down to the rooms.

"I've just done this pre-season for nothing – it's going to be a long year ahead."

West Coast now faces the task of trying to replace its number one defender.

Eagles coach Adam Simpson told 5AA on Wednesday that Jeremy McGovern might need to play a fixed role in defence at various stages depending on the opponent.

"We're going to have to see how we manage the loss of Eric, and (McGovern) might be part of that," Simpson said.

"In the next two or three weeks I need to find out what is our best fit down back.

"He's definitely going to be part of that at stages. If we play teams with a forward line with some dangerous talls, no doubt he's going to have to help us down there.

"But I'd love to swing him forward, too, at some stage."

Mitch Brown seems the logical man to take on the role as the main key defender.

Greater responsibility may also fall on versatile defender Will Schofield, who can play on both talls and smalls.

The Eagles' injury toll is still a major worry.

Ruckman Callum Sinclair will miss a month after breaking his thumb against Carlton.

Nic Naitanui remains a concern after he was left out of West Coast's squad to face Port Adelaide at Norwood Oval on Sunday.

The star ruckman is battling a back issue and is yet to play in the pre-season but the club believes he should be available for the Eagles' final NAB Challenge match against Fremantle on March 22.

Jack Darling's progress from his foot injury remains slow. Simpson admitted on Wednesday that the Eagles were tentatively hoping for the dynamic forward to be ready by round five of the home and away season.

One positive is that vice-captain Scott Selwood appears set to be available for round one following ankle surgery last December, and he may even play against Fremantle in the last NAB Challenge game.