The second-row returns in today’s derby with Leeds Rhinos having served a one-game ban for punching Adrian Morley in their win over Salford Red Devils.
Given the competition for places at Wheldon Road, Cook – who joined from London Broncos over the winter –knows it was foolish.
“I had a bit of a brain explosion the other week and apologised to my team-mates, coaches and fans for that,” said the 28-year-old, who missed Friday’s victory over Hull FC.
“I know I can’t do it again and now have to make sure I do a good enough job to hold my spot. We’ve a few players in the pack coming back from injuries soon – Lee Jewitt and Frankie Mariano – so competition is only going to get tougher.
“Daryl Powell won’t keep you in his team if you’re not delivering the goods so I need a big game against Leeds.”
Cook, who started his career with Bradford Bulls at the height of their rivalry with Rhinos, is relishing the chance to experience an intense derby atmosphere once more.
“There’d be 20,000 there back in the day but now Bulls aren’t in Super League, this Cas game is turning into a big derby itself,” he said.
“I believe it’s near to sell-out and it should be a terrific atmosphere.
“I’ve been fortunate enough to play for Hull KR in the Hull derby and, after not really playing in front of big crowds too often down in London, it’ll be nice to savour that excitement again.”
Cook describes today’s game against the leaders as a “massive opportunity” for Castleford to demonstrate they can compete for trophies.
“We’ve won two on the bounce and a third, against a very good Leeds side, would send out a message to the rest of the league about what we can do,” he said.
“We’re more than capable.”