ESPN President, John Skipper, resigned on Monday, citing a substance addiction.

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

He continued, “I come to this public disclosure with embarrassment, trepidation and a feeling of having let others I care about down.”

The resignation takes effect immediately. In a farewell email to staffers, Skipper said, “It has been my absolute privilege to serve as president of ESPN.”

Skipper is widely seen as one of the most powerful people in both the media and sports worlds.

He managed ESPN’s hugely profitable portfolio at a time of tremendous stress on the cable business.