NICK Malceski's season may be over after coach Paul Roos confirmed the Swans playmaker had ruptured his anterior cruciate ligament during Sunday's NAB Cup loss to Hawthorn in Launceston.

“It looks like [an ACL injury], the doctors are pretty certain,” Roos said shortly after the match.

“It’s obviously disappointing for him and it’s an emotional [time] because you’ve spent the whole pre-season trying training and then you do it. It looks like he’ll be out for a little while.”

Malceski, 23, went to ground just outside the Swans’ defensive 50 two minutes into the third term.

His right knee buckled under him as he looked to change direction and give off a pass.

“It was more of a twisting motion more than anything else,” Roos said. "I think if it’s any consolation to anyone, there’s not much you can do about it.

“It happens. It’s happened to other players and it’s really unfortunate for the kid more than anything else. You can talk about structures and all those things, but it’s more unfortunate for Mal as a player.

“He’s a good guy and you love to see blokes playing. You don’t like to see [Kangaroos forward] Nathan Thompson do it last year and [Adelaide ruckman] Rhett Biglands did his again. You hate seeing that just for the player, rather than anything to do with the club or structures or things like that.

“It’s hard to talk to guys after they’ve just done it. You just pat them on the back and there’s not much more you can do.”

Malceski had his left knee reconstructed in 2002, fighting back to become one of his side’s most important players.

He impressed last year in the defensive playmaker role left vacant by the long-term injury to Tadhg Kennelly.

“I think it shows you how important Marty Mattner coming across the line was,” Roos said, after the former Crow looked poised in a similar role on Sunday.

“Last year we only really had Mal [in that role]. At least this year we’re going to have Tadhg and Mattner. It just means that that trade has become an even more important trade than what we thought it was at the time.”

Malceski will undergo scans in Sydney to confirm the club's diagnosis.