BOSTON — Mired in mediocrity only less than 11 months after setting a team record in victories and winning a World Series, the Red Sox on Sunday night fired Dave Dombrowski, their president of baseball operations.

A formal announcement was expected on Monday, but players were told of the news late Sunday after a 10-5 loss to the Yankees.

Manager Alex Cora called the team together in the clubhouse at Fenway Park after the game and shared the team owners’ decision on Dombrowski, a longtime baseball executive who is one of the few general managers to lead three franchises to the World Series.

“Surprise and shock,” Cora told reporters after the game. He added later: “This is a guy that gave me a chance to come here and be a big-league manager. It’s one of those that caught me. They just told me. So I’m not ready to talk about it.”