Cas travel to St Helens on Friday night having not beaten Saints at their own place since December 1992.
Powell is hoping for a big display from Cook, who is set to make his Tigers debut at Langtree Park.
“This is a good opportunity for Cooky,” Powell said.
“Physically he’s great, a big solid guy, and we’re going to need to be real physical this week so this is a good opportunity for him.
“I’m challenging the pack on a regular basis, verbally up to now, but there’s a little bit of selection in there now too.
“We’re looking for standards to improve consistently. This is a great opportunity to prove we’ve got a little something about us.
“People are probably writing us off at the minute but we’re in there and, I think, looking better physically and defensively so far than we did for large periods of last year.”