BOSTON — Dave Dombrowski was the closer. His old boss, John Henry, hired him four years ago, gave him a deep crop of young talent and told him to win the next Boston Red Sox title as soon as possible. Dombrowski did it last fall, and someday his Hall of Fame plaque will reflect that achievement.

Now the Red Sox need a starter to get them back to the playoffs after this year’s absence, and they decided that Dombrowski, 63, will not be the guy. They fired him as president of baseball operations after Sunday night’s loss to the Yankees, with three assistants as the interim replacements.

Even by the championship-or-failure standards of modern New England sports, this was hard to fathom on its face: A little more than 10 months after winning the World Series, with the team nine games over .500, Dombrowski is out.

“It’s crazy,” Manager Alex Cora said on Monday. “It’s the same thing as thinking that we won 108 games and right now we’re on the verge of getting eliminated. We never thought we were going to be in this spot, and obviously we never thought that this was going to happen.”