Cooke was sent off for butting Brad Drew during the victory over Huddersfield on Saturday and feared that he could miss his club's big day if he was banned for two games or more.
"It's a feeling of relief more than anything," said his coach, John Kear. "He has played at first-team level since 1999 and has only even been sin-binned once and I think that counted in his favour."
Aside from Cooke, Kear will be without Shayne McMenemy at Widnes on Sunday. The second-rower will be resting a shoulder injury ahead of the semi-final, but Gareth Raynor is due to make his comeback.
The London Broncos' New Zealand Test scrum-half James Leuluai will miss the rest of the regular season with a broken ankle. Leuluai hopes to be fit if London make the play-offs and be ready for the Tri-Nations tournament in the autumn.
Kris Radlinski is back in Wigan's side after a six-match absence with a hamstring injury and his coach, Ian Millward, believes that he will be a rejuvenated player now that he has committed his future to the club rather than switching to rugby union.
"Kris looked like he had the weight of the world on his shoulders," Millward said. "He looked a little bit withdrawn as he contemplated his future, but now he's very bubbly. The Wigan captain is now looking forward to taking on Wakefield on Friday night. "I've trained so hard in the last couple of weeks," he said.
Saints' coach, Daniel Anderson, plans to rest Keiron Cunningham and Paul Wellens from Friday's match at Leigh, with the following weekend's semi-final in mind, but Vinnie Anderson and Jason Hooper are expected to return.
Owen Craigie's future at Widnes could be determined by a specialist's examination on his knee this week. Craigie is contracted for next season, but that will be void if Widnes are relegated, as now seems likely.
Next season's French newcomers to Super League, Les Catalans, are to announce another major signing today.
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