Cardinals first baseman Lance Berkman rescheduled Thursday's surgery on his right knee for this morning due to a scheduling conflict involving an attending orthopedist. Today's procedure probably will determine whether Berkman will appear again for the Cardinals this season, or for any club in the next 6-12 months. Berkman suggested earlier this week that today's outcome could cause him to weigh retirement based on its rehab. Berkman's knee buckled during last Saturday's game against the Los Angeles Dodgers, causing significant damage to the surrounding meniscus and other cartilage. Berkman disclosed Thursday that today's procedure may be the first of a two-step process should Houston orthopedist Dr. Mark Adickes and attending orthopedist Dr. Tom Clanton determine that he requires a replacement of his anterior cruciate ligament. Berkman's season would be over if the procedure is necessary; however, Berkman may have to wait up to two months for the actual transplant. Berkman cited the "potential complexities" of the surgery as a major reason why he asked for Thursday's delay. A former Rice University and Houston Texans team orthopedist, Clanton is very familiar with Berkman's medical history and is the reason Berkman initially planned to visit the Steadman Clinic in Vail, Colo., for the procedure. Clanton currently serves at the clinic. Berkman required an ACL replacement on the same knee in November 2004. Because of that, Adickes may remove the ligament and graft bone into holes where the original transplant was woven through the thighbone and shinbone. Recovery is estimated at 6-12 months. Another possible procedure involves microfracture, or drilling holes into a bone to promote regeneration of cartilage sheared from the area when Berkman stretched for a throw from shortstop Rafael Furcal last weekend at Dodger Stadium. Otherwise, Berkman's condition would approach bone on bone. Berkman would remain on crutches unable to place any weight on the leg for at least six weeks following the procedure.