Fehr announced last month that he will resign as executive director of the Major League Baseball Players Association, a post that he has held for a quarter-century. Weiner will officially be voted in as the next union head at some point after the 2009 season is complete. Fehr will step down no later than March 31, 2010.
So what is Weiner's top priority for when the job officially becomes his?
"I think there's really only one priority that the executive director of a labor union has, and that is to maintain the cohesiveness, the unity, the solidarity of the membership," said Weiner, the general counsel of the union. "To find out what priorities the players have and to formulate a strategy for best pursuing those priorities. There's a lot of other things that the union does, and that will be my responsibility to oversee in terms of legal affairs and licensing and business affairs.
"But there's really only one priority, and that's making sure that I understand what the needs of the players are, and that we figure out the best way to further those needs."
Though many union members are already familiar with Weiner, he will formally meet with as many players as he can during these weeks of transition.
"He'll let them know how he sees things, what the future holds in his view, how he intends to attack it," said Fehr. "He will answer any questions that they have. And after that, the membership will vote."
The vote for Weiner is expected to be a slam dunk.
"Honestly, it will be sad to see Don go," said D-backs right-hander Dan Haren. "He's been an unbelievable leader for our Players Association, the strongest players union in sports for the last 25 years. With that said, being in union meetings over the past couple of years and seeing Mike in action, I think it will be a very smooth transition. The players I've spoken to on my team and other teams feel the same way. We have all the confidence in the world in him and we're excited to get going."
The players look forward to a stable changing of the guard.
"I'm actually -- I'm not excited that somebody is leaving, but at least we know we're getting somebody that's been familiar with everything we've been trying to do and the things that are important to us," said Red Sox ace Josh Beckett.
Fehr will be missed by his constituents.
"I just want to wish Don the best of luck," said Red Sox veteran Tim Wakefield. "He's done an outstanding job as our executive director of the Players Association and I hate to see him leave, but I'm also proud for Mike to take his place and I just wish Don the best of luck in his future endeavors."
While Weiner gets prepared to take over, Fehr knows that the success of the union is about so much more than one person.
"The executive director can do a lot of different things," said Fehr. "He can be a spokesman, he can negotiate, he can get involved within legal proceedings, the arbitration cases. He can get involved in any of the day-by-day activities. He's got to maintain a staff, do budgets. All of that kind of thing that comes with it, including the negotiations themselves.
"But you have to have a lot of strong people around you to do that. And the only thing which nobody else can do is the thing Mike just mentioned, and that's the critical thing. That is maintaining the trust and confidence of the players and their unity and cohesion as close to 100 percent as we can do it. Players have, I think, an overwhelming degree of trust and confidence in Mike, who has certainly earned it over the years. And that's what he's going to spend a lot of time doing. Everything else will fall into place after that."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.