Melbourne: After a year at the helm of the ATP World Tour, Brad Drewett has been diagnosed with motor neurone disease and will be replaced as executive chairman and president.

Drewett, a former player, will continue in his role on an interim basis until a successor is found “in the near future,” the ATP said in a statement Tuesday.

His speech was noticeably slurred when Drewett attended a news conference on Saturday to announce a new racket sponsor for the ATP Tour. Remarks on behalf of the ATP were made by a member of the group’s marketing department.

The 54-year-old Australian was a top 40 singles and top 20 doubles player before he retired as a player in 1990. He has held the top ATP position since January 1 last year, but had previously led operations in the Middle East, Asia and the Pacific regions since 2006.

“It has been a privilege to serve as executive chairman and president of the ATP, an organisation that I’ve been a part of for more than 35 years since I became a professional tennis player,” Drewett said in a statement. “I hold the ATP very close to my heart, and it’s with sadness that I make the decision to enter this transition period due to my ill-health.”

Roger Federer, president of the ATP Player Council, said the news was difficult for the tour and its players:

“Brad has become a good friend of mine over the years and this is very sad news for all of us at the ATP and the entire tennis community,” the 17-time major winner said in a statement. “He is well-liked and respected by everyone and has done a tremendous job in leading the ATP over the past 12 months, overseeing some major initiatives and a record-breaking year in 2012. His dedication and service to the sport over the years has been truly admirable and he has been a central figure in helping to grow the ATP product across the globe. “

After his first-round win at the Australian Open on Tuesday, Federer said he’d spoken to Drewett on Monday and was “Obviously very emotional.”

Murray said it was “shocking news.”

“He’s definitely had an impact in the time he’s been working there,” Murray said. “It’s a big shame.”

Motor neurone disease is known as Amyotrophic Lateral Sclerosis (ALS) in many parts of the world, and as Lou Gehrig’s disease in the United States, where it was named after the former major league baseball player who had to retire from the sport when diagnosed with the illness.

It affects voluntary muscle activity including speaking, walking, breathing, swallowing and general movement of the body and usually causes progressive disability.

WTA chairman Stacey Allaster said, “the thoughts and prayers of the WTA family are with Brad, his family and the entire ATP community at this very difficult time.”

“We know he will fight this terrible disease every step of the way, and have our full support for whatever he needs.”

Drewett’s one year in the job was not an easy one. Within days of taking the job last January, he was forced to reduce tensions after rumours of a potential player strike surfaced at Melbourne Park.

Most of the complaints were about player compensation for the lower-ranked players, and for increased prize money for the earlier rounds of Grand Slams, both of which have been addressed and improved at this year’s Australian Open.

And beginning this year, the ATP decided to more strictly enforce the 25-second rule between points in an effort to speed up play.

As recently as the weekend, Drewett said he had planned to meet with the players to discuss the rule tightening.

“It’s only been two weeks, and like anything else, change takes time and for the players to adjust,” Drewett said. “So I’ll have a better idea of how they feel after that. I’ve heard some reports, but it will be good to get the players’ feedback directly.”

International Tennis Federation president Francesco Ricci Bitti said Drewett was widely respected for his pioneering work in developing the game and his friendly demeanor.

“We were very happy to support him when he worked through the ATP International Group and then the Tennis Masters Cup to help to open the great country of China to our sport which will always be noted as one of his outstanding achievements,” Ricci Bitti said. “For the ITF and for me personally, he is more than a colleague, he is a friend, and I want Brad to know we are available to do whatever is needed to help support him and his family.”