Defender Orr and Scotland striker Clarkson missed the midweek Carling Cup defeat at home to Carlisle through illness and both could make an instant return as Johnson looks for an immediate response to the shock loss.
Jamie McAllister could miss the clash, though, after limping out of the Carlisle game with an Achilles problem.
Striker Nicky Maynard should come straight back into the side after missing the Cumbrians clash with a knock, with John Akinde likely to drop out.
Johnson kept his players locked in the dressing room for over an hour following the 2-0 reverse and will be looking for a reaction from his squad who also lost 3-0 at Cardiff last weekend.
One man that will not be involved is Lee Trundle, who has rejoined Swansea on-loan until January 1.