AUBURN HILLS >> Well, if 7-foot-4 backup center Boban Marjanovich gets hurt, the Detroit Pistons will have a ready-made replacement.The team announced Saturday it had signed 7-foot-6, 300-pound center Mamadou N'Diaye to a contract.Terms of the deal were not disclosed.The native of Senegal who played at University of California Irvine - averaging 12.