NEW YORK (AP) _ The Japanese commissioner's office has sent a letter to the major league commissioner's office accusing the New York Yankees of tampering with pitcher Hideki Irabu.

Bill Murray, the executive director of baseball operations at the major league commissioner's office, received the letter and passed it on to acting commissioner Bud Selig, a baseball official said Thursday on the condition he not be identified.

Irabu is also closing in on a multiyear deal with the Yankees worth in excess of $13 million, the source said. New York has until May 31 to reach an agreement with Irabu, or else the pitcher's rights revert to the San Diego Padres.

San Diego agreed to a deal in January with Irabu's team in Japan, the Chiba Lotte Marines of the Pacific League, to obtain the pitcher's rights. But Irabu refused to deal with the Padres, saying he would sign only with the Yankees.

On April 22, the Padres dealt his rights to the Yankees for $3 million. As part of the trade, the Yankees will send injured outfielder Ruben Rivera and minor league pitcher Rafael Medina to San Diego in return for three minor-leaguers: second baseman Homer Bush and outfielders Gordon Amerson and Vernon Maxwell.

The deal, however, is conditioned on Irabu signing with the Yankees by May 31.

Many in baseball have thought that the Yankees attempted to negotiate with Irabu while his rights were with the Marines or the Padres. The issue could become touchy for baseball because Yankees owner George Steinbrenner is suing the other 29 teams and the sport's central offices, claiming they are illegally interfering with his marketing deal with Adidas.

Irabu was 12-6 with a 2.40 ERA last year, leading the Pacific League in ERA for the second straight season.

The Yankees could not immediately be reached for comment. Baseball spokesman Rich Levin declined comment.