SWANS coach Paul Roos has "'been there, experienced that" when it comes to slow starts to the season, so he know it will be vastly different when his team clashes with Port Adelaide this weekend.

Sydney met last season's grand finalists in round two this year, and it proved a very lopsided contest, with the Swans winning by 11 goals at the SCG.

But Roos knows all about teams having early-season slumps, and expects Port to be a much tougher task tomorrow.

"Having been in a situation where Port were [in 2006 and 2007, when the Swans played until the last game of the season], you know it's hard early in the next season," Roos explained. "They were a little behind where we were because we got beaten in the first round of the finals. We knew they would be an bit underdone but that changes now.

"They are fitter now, they are playing much better footy and are a much different side to when we played them earlier in the season."

Roos was speaking from experience, as the only time Port have beaten the Swans in their past five meetings was in round two back in 2006, the season after Sydney won the flag.

The coach has been forced to make one change to the team that comprehensively defeated Essendon last weekend, with backman Tadhg Kennelly out with a knee injury, replaced in the squad by youngster Tim Schmidt.

Nick Malceski, who has a game of fitness to his credit after miraculously returning from knee surgery after just 12 weeks last weekend, will be able to slot into Kennelly's role.

"Obviously we lose a lot with Tadhg," Roos said.