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.