According to sources at HBO, if Eliseo Castillo pulls out against Wladimir Klitschko for their tentatively scheduled April 23 bout in Dortmund Germany, the network is (thankfully) seriously considering pulling the plug on a Wladimir Klitschko fight. Boxingtalk.com understands that HBO will not approve Leo Nolan as a replacement to Castillo, but of course, this is the Klitschko's we're talking about, so one never knows what extremes HBO will go to before they make a final decision.  Remember where you heard it first! (12:55 AM ET)