I would guess he will want to get Philbin and Hudson back up to match fitness and playing in the squad as the first priority, if so that would mean leaving out Thomas, Reddecliffe and Whitehead. He could perhaps rest Casiano or Vaughan though as an alternative.
Then unless there is a HB injury Leon Hayes would be the fourth player to drop out as I don't think Powell would want to disturb the Williams Drinkwater partnership as it really seems to be coming together nicely.
After that, the team picks itself with Russel coming in for Thewlis and Dudson joining Philbin on the bench.