John Beilein has resigned as head coach of the Cleveland Cavaliers after a short stint at the helm.

Beilein joined the Cavaliers from college team Michigan on a multi-year contract in May, but stepped down on Wednesday.

The 67-year-old – who oversaw an Eastern Conference-worst 14-40 record this season, only behind the Golden State Warriors (12-43) in the entire league – will be reassigned to a different role in Cleveland, where J.B. Bickerstaff will take over from Beilein.

"Over these last nine months, I have given my all to this organisation, but after much reflection, I have decided that it is best that I step back and resign from my position as head coach of the Cleveland Cavaliers and assist the organisation in a different capacity," said Beilein, who spent the previous 12 seasons as coach of Michigan.

"I am very grateful to Dan Gilbert, Koby Altman and the entire Cavaliers organisation for the opportunity they have provided me.

"This was a very difficult decision for me, but I want to be clear – this was my decision to step down and I truly appreciate the understanding and support of the front office during this time. I find losing very challenging and this year has taken a much bigger toll on me than I expected.

"I grew concerned for the consequences this toll could potentially take on my own health and my family's well-being down the road. I was not certain I could be at my best for the remainder of the season and in the future. That would not be fair to the players, coaches and support staff.

"I also would not be doing this now, during the season, if J.B. Bickerstaff was not ready and capable to assume the head coaching role immediately and continue the rebuilding process that we have started.

"For 45 years and more than 1,300 games, my journey as a basketball coach has been a dream come true. I have never been afraid of a challenge and have given each one my all – sometimes to the detriment of my own well-being. I want to thank my wife, Kathleen, for being by my side and I appreciate the outpouring of support from family, friends, and colleagues during this time. I look forward to being able to spend more time with my wife, kids and grandchildren over the coming months."

Cavs general manager Koby Altman added: "John Beilein is one of the more accomplished basketball coaches in the history of our game and while it's unexpected, we understand and respect his decision to step down as head coach of the Cavaliers.

"I was excited about the development of our young players, who have all shown growth and maturity under coach Beilein. We are thankful for the time he spent as head coach with the Cavaliers and are looking forward to his continued contribution.

"The NBA is a unique business that sometimes requires aggressive risk-taking on important long-term decisions to move a franchise forward and ultimately compete for championships. I would like to thank the incredible fans of the Cavaliers for their support in both good and challenging times. Building a strong culture will continue to be the top priority here at the Cavaliers."