I'd leave Hardaker at centre and Escare fb benching Sarge.
Lam will rest the young lads unless someone pulls out late notice.
Escare,
Marshall, Hardaker, Gildart, Burgess, Williams, Leuluai, Flower, Powell, Bullock, Hankinson, Greenwood, O'Loughlin.
Bench - Tautai, Partington, Isa & Sarginson.
With Escare ar fb we have a very fast back three and pace is something Cas lack, bar Eden.
Replacing Isa with Hankinson is adding size to the pack which is how they worked us over at their place.