As of mid-August, baseball?s investigators looking into the use of performance-enhancing drugs still wanted to speak with at least 45 current and former major league players, most of them still active. The number emerged in a letter the union sent Aug. 23 to the head of the investigation, the former Senator George J. Mitchell, in which the union said it would let him know if any of the 45 players changed their minds about not wanting to be interviewed. The letter was read to a reporter for The New York Times by a person representing one of the players. Steve Fehr, a lawyer working on behalf of the union, declined to comment on the letter?s content.