The baseball players' association says any suspensions resulting from the sport's latest drug investigation likely won't be served until next year if the discipline is challenged before an arbitrator.

Union head Michael Weiner says he expects Major League Baseball to notify the union of its plans for penalties in the next month, and the union will maintain that any discipline should not be announced until after arbitrator Fredric Horowitz upholds a ban.

Weiner says that because of the time needed to prepare and hold hearings, the case of any player challenging a penalty won't be decided during this season.

Former MVPs Alex Rodriguez and Ryan Braun are among the players under investigation for ties to Biogenesis, a closed anti-aging clinic linked with the distribution of performance-enhancing drugs.

ESPN's "Outside the Lines" has reported that Rodriguez and as many as 20 other players are expected to be suspended for their relationship to Biogenesis founder Anthony Bosch, who allegedly provided performance-enhancing drugs to the players. Rodriguez has denied the allegations.

When asked directly about his involvement with Biogenesis on Monday, Rodriguez said, "I appreciate you asking that question. But due to the process, we're not allowed to comment on that. But with due time, we'll talk about that."

MLB commissioner Bud Selig, appearing Monday night on the "Late Show with David Letterman," said "only time will tell" when asked whether Rodriguez would ever play for the Yankees again.

"We're in the midst of a very thorough and tough investigation on all of this because I really believe it's not only the right thing to do, we're going to do it," Selig said.