Negotiators for baseball players and owners have begun what figures to be lengthy and acrimonious collective bargaining negotiations to replace their labor contract that expires Dec. 1, with management likely to propose a salary cap system the union has vowed never to accept.

Tony Clark has resigned as head of the Major League Baseball Players Association, the union announced said, as a possible salary cap fight looms during a federal investigation of its finances.

When baseball players agreed a decade ago to restraints on signing bonuses for draft picks, then union head Michael Weiner said matters could be revisted if the provisions didn't work to players' satisfaction.