NEW YORK — Michael Weiner, the plain-speaking, ever-positive labor lawyer who took over as head of the powerful baseball players' union four years ago and smoothed its perennially contentious relationship with management, died Thursday, 15 months after announcing he had been diagnosed with an inoperable brain tumor. He was 51.

NEW YORK — Michael Weiner, the plain-speaking, ever-positive labor lawyer who took over as head of the powerful baseball players' union four years ago and smoothed its perennially contentious relationship with management, died Thursday, 15 months after announcing he had been diagnosed with an inoperable brain tumor. He was 51.

The Major League Baseball Players Association said Weiner died at his home in Mansfield Township, N.J.

"Michael Weiner worked even thru his sickness. He didn't look at it as an excuse to quit," tweeted Pittsburgh's Andrew McCutchen, the NL MVP. "He never gave up on us even when at his worst."

As Weiner's health deteriorated this summer, a succession plan was put in place. Former big league All-Star Tony Clark took over Thursday as acting executive director and is to be approved as Weiner's successor when the union's board meets from Dec. 2-5 at La Jolla, Calif.

"Words cannot describe the love and affection that the players have for Michael, nor can they describe the level of sadness we feel today," Clark said in a statement. "Not only has the game lost one of its most important and influential leaders in this generation, all involved in the game have lost a true friend."

Baseball Commissioner Bud Selig called Weiner "a gentleman, a family man, and an extraordinarily talented professional who earned the trust of his membership and his peers."

"Our strong professional relationship was built on a foundation of respect and a shared commitment to finding fair solutions for our industry. I appreciated Michael's tireless, thoughtful leadership of the players and his pivotal role in the prosperous state of baseball today," Selig said in a statement. "Michael was a courageous human being, and the final year of his remarkable life inspired so many people in our profession."

At Weiner's last public speaking engagement, a 25-minute meeting with baseball writers on the day of the All-Star game in July, he was confined to a wheelchair and unable to move his right side. Yet, he wanted to respond to questions about his illness and issues in the game, and did so with the grace and humor he was known for throughout his life.

"I don't know if I look at things differently. Maybe they just became more important to me and more conscious to me going forward," he said. "As corny as this sounds, I get up in the morning and I feel I'm going to live each day as it comes. I don't take any day for granted. I don't take the next morning for granted. What I look for each day is beauty, meaning and joy, and if I can find beauty, meaning and joy, that's a good day."

Weiner first experienced weakness and tingling on his right side in July 2012 and was diagnosed with a glioma the following month. By June 2013, he had experienced a rapid increase in symptoms. As he sat in a wheelchair in foul territory at Citi Field the following month before the All-Star game, players lined up to speak with him.

His voice had gotten raspy by early August, when he responded on behalf of the union to drug suspensions handed down to Alex Rodriguez, Ryan Braun and other players.

Weiner was hired by the union as a staff attorney in 1988 and wound up succeeding Fehr in December 2009. Weiner became just the fourth head of the organization since 1966.

"Here you had an individual who came to me as a kid for his first private sector job," Fehr said in a telephone interview with the AP. "He impressed me at the time and ever after with his intelligence, his dedication, his innate sense of fairness, his focus on finding what the right thing was to do and then doing it. This was an extraordinary individual all the way around."