Yankees third baseman Aaron Boone injured his left knee playing basketball and may be out for the season.
Boone was hurt a week ago and may have torn an anterior cruciate ligament. The extent of the injury will not be known until swelling subsides. He has not yet been examined by Yankees' doctors.
If there is a complete tear, he would need reconstructive surgery that could sideline him until 2005.
"We are evaluating the extent of the injury and expect to solicit multiple opinions before providing a complete diagnosis," general manager Brian Cashman said.
The Yankees do not have a backup third baseman with full-time experience. Enrique Wilson and Miguel Cairo are options, as is minor leaguer Drew Henson.
New York acquired Boone from Cincinnati July 31, and his 11th-inning homer off Red Sox knuckleballer Tim Wakefield in Game 7 of the ALCS won the pennant.
He agreed Dec. 1 to a $5.75 million, one-year contract, which contained language saying it would become nonguaranteed if he played basketball.
Boone is eligible for free agency after next season, and if the Yankees successfully converted the deal to a nonguaranteed contract, they could release him and be responsible for only 30 days' termination pay, about $942,000.