That Joe Nieuwendyk, GM of the Stars, who knew he had such a sense of humor? The Post has learned Nieuwendyk told Rangers GM Glen Sather on Tuesday that it would cost the Blueshirts three young studs off the roster, believed to be Marc Staal, Brandon Dubinsky and Derek Stepan, for the privilege of renting Brad Richards. Never mind that Richards, who has a no-move clause in his contract, has not yet been asked for a list of clubs for which he would be willing to waive it, according to agent Pat Morris in a phone conversation yesterday with The Post. Never mind that Richards, the elite center the Blueshirts so desperately need and covet, is still suffering post-concussion symptoms from a Feb. 13 Sammy Pahlsson hit that will prevent him from returning before Monday's trade deadline, though reports are that the impending free agent is having good days.