BOSTON (AP) – Theo Epstein fled Fenway Park on his last day as Boston Red Sox general manager in a gorilla costume. It was Halloween, and the TV paparazzi were none the wiser.

Yes, Epstein said, it was inconvenient to have reporters camped out at his home.

But he didn’t give up what had been his dream job because of the sometimes suffocating interest in the local baseball team, a fascination that became a frenzy after Epstein helped build the Red Sox into World Series champions in 2004.

It was “unfortunate,” he added, that details of his contract negotiations with longtime mentor Larry Lucchino leaked out. And it’s true that the Red Sox lowballed him – the most successful general manager in franchise history – as if he were still a kid.

But that’s not why he left, either.

A “multitude” of reasons, taken together, persuaded Epstein to step down as Red Sox GM on Monday, just one year after ending Boston’s 86-year title drought. In his first public comments on the decision, Epstein would not say exactly why he quit but said a breakdown in the “process” convinced him he couldn’t stay.

“You have to be all-in,” he said. “You have to believe in every aspect of the job and the organization and your ability to stay and do the job the right way, with your whole heart and your whole soul. And in the end, it just wasn’t the right fit. It wasn’t right.”

Now 31, Epstein was an 18-year-old Yale undergrad when Lucchino hired him in Baltimore as an Orioles intern. He followed Lucchino to the San Diego Padres and then to Boston before the Red Sox made him, at the time, the youngest general manager in baseball history.

The move paid off with three straight playoff appearances – unprecedented in franchise history – and the 04 championship. But, along the way, the boy GM outgrew the father-son dynamic. Some accused Lucchino of pushing his protege out in a grab for greater glory.

“If there are reports of a power struggle or meddling on behalf of Larry, that really wasn’t the case,” Epstein said. “Essentially, I felt like I had pretty much a free hand to run the baseball operation the way I saw fit.

“We’ve had a very successful working relationship. I think Larry and I like each other. As with any long relationship, there are complexities. … But in the end, I want what’s best for Larry.

“He’s done a lot for me. I owe him quite a bit, and I take that to heart. Thirty years from now, when I look back on my relationship with Larry Lucchino, I’m going see it as a positive influence in my life.”

Lucchino did not attend Wednesday’s event – the only member of the management group known as “Theo and the Trio” to skip it. Owner John Henry acknowledged Lucchino’s absence and said he wanted to defend his chief executive personally.

“Larry Lucchino has turned this franchise around in every way, shape, or form,” Henry said. “We are all too willing to blame him for this. … I think that’s wrong. I think that’s inaccurate.

“I’ve seen him blamed for everything under the sun. I don’t know how anyone can legitimately think that the principal owner is not ultimately responsible for what happens with the general manager. This was not Larry Lucchino pushing Theo out. I hold myself wholly responsible.”

On the verge of tears at one point, Henry was effusive in his praise of Epstein and called him “a remarkable young man” who selflessly tried to hire Moneyball maestro Billy Beane for the GM job before it was given to him.

“I may not 100 percent agree with his decision. But I believe that a very large part of his decision is driven by a love for the franchise,” Henry said. “This is a great, great loss. I have to ask myself, maybe I’m not fit to be the principal owner of the Boston Red Sox.”

Epstein’s three-year deal expired on Monday, leaving the team without a general manager or assistant GM heading into the offseason; Epstein’s No. 2 man, Josh Brynes, is now the GM in Arizona. The team re-signed reliever Mike Timlin on Wednesday, but the announcement did not say which Red Sox official negotiated the deal.

The Red Sox need to plug holes in the starting rotation and bullpen that led to a first-round playoff sweep by the eventual World Series champion Chicago White Sox. Manny Ramirez and David Wells have reportedly asked to be traded. Center fielder Johnny Damon is a free agent, as are three starting infielders.

And so is Epstein. He has already been contacted by one club through an intermediary, but he sent word that he was concentrating on getting Boston ready for the GM meetings.

“If we get to next week, that would be a more appropriate time for me to listen to what other teams have to say,” he said.

And he will listen.

“I am not burned out,” he said. “I have tremendous passion for the game. I have a tremendous dedication to the game. I believe I will find myself in a position of leadership with an organization again in the future. … Once these guys ship out for the GM meetings, then I can consider the future a little bit more closely.”

Epstein could kill time working with his twin brother on the charity they created called “The Foundation to be Named Later.” Wall Street and Capitol Hill are also possibilities.

“I believe in myself, and that’s one of the reasons why I’m willing to take this step going off into relative uncertainty,” Epstein said. “I have faith in myself to embrace this change in my life and, in the end, I believe it will make me stronger.”

Only subscribers are eligible to post comments. Please subscribe or to participate in the conversation. Here’s why.

Use the form below to reset your password. When you've submitted your account email, we will send an email with a reset code.