WASHINGTON -- Dusty Baker will not return as the Nationals' manager in 2018, the club announced Friday afternoon, a stunning development after Baker's two successful seasons at the helm.
Baker guided Washington to back-to-back National League East titles for the first time in franchise history, going 192-132 for the Nats' best two-year stretch. However, the team fell short of its ultimate postseason goal, losing in Game 5 of the NL Division Series at Nationals Park in both 2016 and '17, and Baker's contract expired at the end of this season.
Both sides had previously displayed public confidence they would be able to negotiate a new contract when the season ended. But in the days following this most recent postseason loss, general manager Mike Rizzo said he and the Nationals ownership came to what he called one of the most difficult decisions he has had to make. Baker was informed Friday morning that he and his coaching staff would not return.
"Our expectations have grown to the fact that winning a lot of regular-season games and winning divisions are not enough," Rizzo said during a conference call Friday. "Our goal is to win a world championship."
Leading up into the postseason, the Nationals believed Baker was the manager to lead them there.

During the club's workout during the NLDS, Rizzo reiterated he was confident Baker would be back in 2018, but they would hold negotiations until after the season. Then the Nats lost, 9-8, to the Cubs in a whirlwind Game 5.
That game caused the Nationals to re-examine how they should proceed, and they did not pick up negotiations with Baker afterward. Rizzo called this strictly a baseball decision.
"After Game 5, we accessed where we're at and where we're going in our organization and our franchise," Rizzo said. "We thought after Game 5 that this was the right decision to make."
Baker would have been the oldest manager in MLB next season at 68 years old, but he showed no sign of slowing down. He spoke openly about how much he enjoyed his tenure in Washington and said he had no plans to retire. Baker has won 1,863 games in his 22-year tenure as a manager, the 14th most in MLB history. Twelve of the 13 managers ahead of him are in the Hall of Fame.
During the past two seasons, Baker had been managing under a two-year, $4 million contract -- well under market value for someone with his pedigree. However, he had signed the deal when he was itching to get back into baseball after two seasons away.
• A letter from the Lerner family
"This was an incredibly difficult decision for us," the Lerner family wrote in a statement shortly after the announcement. "[Baker] is one of the true gentlemen in our sport, and we thank him for the successes that we enjoyed together over the last two years. We wish him nothing but the best going forward."
The Nationals will immediately begin searching for a new manager, who will become the team's seventh skipper since the franchise moved to Washington in 2005. No Nationals manager has completed a third season, and the club's new manager in 2018 will be its sixth in 10 years.
That manager will inherit a loaded roster in 2018 with a strong chance at a third consecutive postaseason appearance. The Nationals made the decision to part ways with Baker on Thursday night, and Rizzo did not believe that instability in the dugout would hinder his hiring process.
"I think we've hired managers in the developmental curve of this organization that fit for us at that particular time," Rizzo said. "In the infancy of the Nationals, we hired managers that could help us build through this thing, and as we got better and as our expectations grew, we went with managers we felt that could get us to the next level.
"That's always been our goal, that's continued to be our goal, but as the managers came and went, they were indicative of where we were in the development curve in the organization."