Serena withdraws with leg injury

NEW YORK -- Serena Williams has pulled out of an exhibition at Madison Square Garden because of a left leg injury.

Williams announced her withdrawal from the BNP Paribas Showdown for the Billie Jean King Cup on Thursday. She'll be replaced in the four-player field by former No. 1 Ana Ivanovic.

The 12-time Grand Slam singles champion was to face Kim Clijsters on March 1 in what would have been their first meeting since Williams' infamous tirade during the semifinals at the 2009 U.S. Open that drew a record $82,500 fine.

The leg injury has forced Williams to miss tournaments in Paris and Dubai.

Williams' sister, Venus, will play Svetlana Kuznetsova in the other semifinal at the one-night event in New York.