In a shock to the sports and TV world, longtime ESPN chief John Skipper is resigning as a result of what he described as a long-term problem with substance addiction.

George Bodenheimer, Skipper’s predecessor as ESPN boss, will serve as acting chairman while Disney searches for a replacement.

“I have struggled for many years with a substance addiction. I have decided that the most important thing I can do right now is to take care of my problem,” Skipper said in a statement.

Skipper has been with ESPN since 1997 and took the reins as president from Bodenheimer in on Jan. 1, 2012. He has also served as co-chairman of the Disney Media Networks wing alongside Ben Sherwood, president of Disney/ABC Television Group.

“I join John Skipper’s many friends and colleagues across the company in wishing him well during this challenging time,” said Disney chairman-CEO Bob Iger in a statement. “I respect his candor and support his decision to focus on his health and his family. With his departure, George Bodenheimer has agreed to serve as Acting Chair of ESPN for the next 90 days to provide interim leadership, help me identify and secure John’s successor, and ensure a smooth transition.”

Skipper’s hasty exit comes at a heady time for Disney has the company last week announced a $52 billion-bet on buying up key assets from 21st Century Fox, including its 22 regional sports networks. Those outlets will be a crucial building block for ESPN’s diversification. The integration of those businesses with ESPN’s established operations is sure to be a Herculean task.

Moreover, the prospect of some of Fox senior managers coming into the Disney orbit if the deal is approved by federal regulators has spread uncertainty across both companies, particularly on the TV side. The Skipper news is particularly surprising as there had been rumblings in sports media circles that he was about to sign a long-term contract extension with Disney.

But Skipper had already been under fire for personnel issues at ESPN in recent months. Morale in Bristol, Conn., has been challenged by a steady stream of layoffs as the once-invincible sports powerhouse adjusts to cord-cutting and a changing business climate. Disney is scheduled to launch an ESPN-branded standalone streaming venture next year, another initiative that will demand strong leadership.

Bodenheimer, meanwhile, headed ESPN during its go-go growth years from 1998 through 2011.

Here is Skipper’s full statement, as reported by ESPN.com:

Today I have resigned from my duties as President of ESPN. I have had a wonderful career at the Walt Disney Company and am grateful for the many opportunities and friendships. I owe a debt to many, but most profoundly Michael Lynton, George Bodenheimer and Bob Iger.

I have struggled for many years with a substance addiction. I have decided that the most important thing I can do right now is to take care of my problem. I have disclosed that decision to the company, and we mutually agreed that it was appropriate that I resign. I will always appreciate the human understanding and warmth that Bob displayed here and always. I come to this public disclosure with embarrassment, trepidation and a feeling of having let others I care about down. As I deal with this issue and what it means to me and my family, I ask for appropriate privacy and a little understanding.

To my colleagues at ESPN, it has been a privilege. I take great pride in your accomplishments and have complete confidence in your collective ability to continue ESPN’s success.

Related stories

Fox's Regional Sports Outlets Could Serve as Balm for Disney's ESPN

ESPN Says Streaming Boosts Live Viewer Ratings

ESPN to Drop 150 Employees in Latest Round of Layoffs

Subscribe to Variety Newsletters and Email Alerts!