"I understand this decision," Valentine said in a statement released by the team. "This year in Boston has been an incredible experience for me, but I am as disappointed in the results as are ownership and the great fans of Red Sox Nation. ... I'm sure next year will be a turnaround year."
A baseball savant who won the NL pennant with the New York Mets and won it all in Japan, Valentine was brought in after two-time World Series champion Terry Francona lost control of the clubhouse during an unprecedented September collapse.
But the players who took advantage of Francona's hands-off approach to gorge on fried chicken and beer during games bristled at Valentine's abrasive style.
More importantly, they didn't win for him, either.
"We felt it was the right decision for that team at that time," general manager Ben Cherington said on Thursday in an interview at Fenway Park. "It hasn't worked out, because the season has been a great disappointment. That's not on Bobby Valentine; that's on all of us. We felt that in order to move forward and have a fresh start, we need to start anew in the manager's office."
Under Valentine, the Red Sox started 4-10 and didn't break .500 until after Memorial Day. By August, when the contenders were setting their playoff roster, the Red Sox knew they would not be among them and traded several of their best players and biggest salaries to the Los Angeles Dodgers.
Without Adrian Gonzalez, Carl Crawford and Josh Beckett, the Red Sox will save $250 million in future salaries and have a chance to rebuild over the winter.
But that will be too late for Valentine.
"We have gratitude for him, respect for him and affection for him, and we're not going to get into what his inabilities were, what his issues were," Red Sox president Larry Lucchino said. "I just don't think it's fair."
Cherington, who replaced Theo Epstein last offseason, will lead the search for a new manager. The team's top target is current Toronto manager and former Red Sox pitching coach John Farrell, who has a year left on his deal with the Blue Jays.
Cherington said he has thought about potential successors but declined to comment on specific individuals. He said he is looking for someone "who can establish a culture in the clubhouse that allows players to perform, and sets a standard."
"And we need to find a person that can bring some stability to that office," Cherington said. "When we hired Bobby, the roster was fairly mature and we felt, mistakenly, in retrospect, that we had a chance to win and the team was ready to win. We're now at a different point. We're trying to build the next good Red Sox team, so it's a little bit different."
A year after a 7-20 September cost the Red Sox a chance at the postseason, the club went 7-22 in September and October to close its worst season since 1965. Boston lost its last eight games, failing even in its role of spoiler as it was swept down the stretch by playoff contenders Tampa Bay, Baltimore and the rival New York Yankees.
That left the Red Sox in last place 26 games out for the first time since 1992 and out of the playoffs for the third year in a row.
"This year's won-loss record reflects a season of agony. It begs for changes," Lucchino said. "We are determined to fix that which is broken and return the Red Sox to the level of success we have experienced over the past decade."
What was supposed to be a season of celebration for Fenway's 100th anniversary was instead the worst under the current management, which bought the team in 2002. And though injuries probably doomed the Red Sox anyway they used a franchise record 56 players Valentine's clumsy handling of his players forced him into frequent apologies that undermined his authority in the clubhouse.
"There's no single reason why we had this dismal of a season," Lucchino said. "But certainly the epidemic of injuries and the injuries to key players were major factors. ... Do I think there's an element of unfairness, given the shortness of his duration, given the injury problems. ... I think there is."
The Red Sox had the AL's best record and a nine-game lead in the wild-card race on Sept. 1, 2011, before missing out on a playoff berth on the final day of the season. Francona, who led the Red Sox to Series titles in 2004 and again in 2007, was let go after admitting that he had lost his touch in the clubhouse.
To replace him, the Red Sox picked Valentine, who took the New York Mets to the 2000 World Series and won a championship in Japan but hadn't managed in the majors in 10 years. The move was an intentional and abrupt attempt to change a culture that enabled pitchers to drink beer and eat fried chicken in the clubhouse during games on their off-nights.
On that, Valentine delivered immediately: He banned beer from the clubhouse, and didn't hesitate to criticize his own players publicly something Francona took pains to avoid.
But even before the season began, injuries began tearing the roster apart.
Crawford missed much of the season, joining pitchers John Lackey and Daisuke Matsuzaka on the disabled list before opening day. Potential closers Andrew Bailey and Bobby Jenks had offseason surgery; Jacoby Ellsbury, David Ortiz, Clay Buchholz, Dustin Pedroia, Beckett and Youkilis also spent time on the DL.
And many of those who remained resented the new accountability.
Kevin Youkilis lashed back after Valentine said he wasn't as "into the game" as before, and Pedroia came to his teammate's defense, saying, "That's not the way we go about our stuff around here."
"He'll figure that out. The whole team is behind Youk. We have each other's backs here," Pedroia said. "Maybe that works in Japan."
In August, management gave up on 2012 and unloaded several of the team's most burdensome salaries on the Dodgers. Los Angeles also missed the playoffs.
Although Cherington openly conceded the season, Valentine refused to do so. Asked during his weekly radio show if he had "checked out," Valentine jokingly said he should punch the host in the nose. (He showed up for their next interview with boxing gloves.)
In mid-September, with Boston's Triple-A team in the playoffs and reinforcements scarce, Valentine called the Red Sox "the weakest roster we've ever had in September in the history of baseball."
Again, he was forced to backtrack.
(But, again, he was probably right.)
Ultimately, Valentine will be judged on his record.
And it was dreadful.
"I don't know how it could be more challenging than this season," Valentine said after saying goodbye to his players following Wednesday night's season-ending loss to the Yankees.
"As I told them, they're not defined as people by their record or the season. They're defined by who they are, not what they are. They were part of a really lousy season, but they gave a hell of an effort every day."