“Steve Phillips is no longer working for ESPN,” the network said in a statement. “His ability to be an effective representative for ESPN has been significantly and irreparably damaged, and it became evident it was time to part ways.”

Last week, The New York Post’s report about the short affair between Phillips and Brooke Hundley became a nationwide story, creating a serious public problem for the network. Before this season, he was elevated from work as a full-time studio analyst into the “Sunday Night Baseball” booth with Jon Miller and Joe Morgan.

Steve Lefkowitz, Phillips’s agent, said in a statement, “Steve Phillips is voluntarily admitting himself to an inpatient treatment facility to address his personal issues.” Lefkowitz said he informed ESPN on Friday of Phillips’s intention.

ESPN took action against Phillips when it learned of the affair, then announced last week that it had granted him a leave of absence. But since Wednesday, the affair became front-page news and an object of ridicule for ESPN, particularly on Deadspin.com.

A letter from Hundley to Phillips’s wife, Marni, which became part of a report filed with the police in Wilton, Conn., turned into salacious fodder.

When Phillips was the general manager of the Mets, he was forced to take a leave of absence in 1998 because of a series of affairs and an accusation of sexual harassment by a Mets employee. He entered counseling and returned to the Mets, but was eventually fired in 2003.