Forward Justin Koschitzke and utility player Matthew Ferguson have been replaced by midfielder Andrew McQualter and former Cat Charlie Gardiner.
Koschitzke jarred a knee in last Sunday's loss to the Western Bulldogs at Telstra Dome and, though he played out the game, moved gingerly.
He was listed as 'test' earlier in the week.
Gardiner will play his sixth match for the Saints as the Swans welcome back spearhead Barry Hall after a seven-week suspension and broken wrist.
