SYDNEY Swans coach Paul Roos expects it won't be long before his outgoing Port Adelaide counterpart, Mark Williams, lands another job in the AFL system.

Williams announced on Friday afternoon that he had agreed to step down after the round 15 clash against Collingwood at AAMI Stadium, ending a 12-year stint at Alberton that reaped the club's inaugural premiership in 2004.

Roos said it was "a sad day" to see Williams' reign at Port Adelaide come to an end, but he expressed confidence in his ability to find a new position.

"It's obviously all happened really, really quickly. He's too good a coach and too good a football mind to not be involved somewhere," Roos said of Williams, shortly after news broke of the Power coach's decision to break ties with his club.

"I suspect the dust will settle and the first thing is for them to appoint a coach for that team, and for Choco to sit back and work out what he wants to do.

"I think he's too valuable a commodity to be out of the game for too long."

Roos said he had enjoyed a good relationship with Williams during the eight years they had matched wits as senior coaches of their respective sides.

"He's been a terrific coach and to do what he did over a long period of time was very good," he said.

"He and I have always got on really well. We've exchanged ideas on things like the LARS [surgery] with David (Rodan) and obviously Nick (Malceski). I'll be sad to see him go."

Roos dismissed a light-hearted suggestion that he was a contender to replace Williams at Port Adelaide and played a straight bat at suggestions that the Power coach would be a good fit at Team GWS.

However, the Swans coach said he had ceased to be surprised by any developments in the football world, adding that Williams had earned a winning farewell from Alberton.

"I believe he's coaching tonight and hopefully they go well for him tonight. He deserves a good farewell from his playing group and I'm sure they'll give as much as they possibly can," Roos said.

"To be perfectly frank, you don't get too surprised by too much anymore in the industry that we're in."