One year after winning 96 games, a division title and National League Manager of the Year, Williams was fired with a year remaining on his contract. This time around, the Nationals should look at experienced candidates, says The Post's Adam Kilgore. (Thomas Johnson/The Washington Post)

Two years ago, the Washington Nationals hired Matt Williams as manager, eschewing experience for youth and energy. Believed to be on the verge of a deep playoff run, the Nationals — led by General Manager Mike Rizzo — wanted Williams, who had never managed in the major leagues, to lead them to the World Series.

But after winning the National League East title a year ago, Washington endured a tumultuous and disappointing 2015 season, missing the postseason and winning 13 fewer games than the year before. So on Monday morning, after much evaluation and conversations with players and team owners, Rizzo told Williams he would not return in 2016.

“Really a tough day here at Nationals Park,” Rizzo said Monday afternoon in a conference call with reporters. “Tough day for me personally, a tough day for our entire organization, but these are the first of the decisions we have to make as we meticulously evaluate why the 2015 season didn’t go the way we hoped. It wasn’t our best year. It wasn’t Matt’s best year. It wasn’t my best year. As an organization, it wasn’t our best year.”

For the fifth time in seven years, the Nationals will turn to a new skipper. The search promises to be more expansive than the one that settled on Williams — an admission by Rizzo that experience is, in fact, important in leading a championship-caliber team.

“Last time, we brought in managing candidates with little or no managerial experience,” he said. “I think we’ll have a greater pool of manager candidates this year, stemming from very experienced to limited experience, and really go through a process that gets to know the manager personally first, and then professionally and what he does on the field.”

Williams’s staff — which includes longtime coaches and beloved bench boss Randy Knorr, a finalist for the manager’s job last time — was also dismissed, although Rizzo said some were offered minor league positions.

Expected to repeat as NL East champions and contend for their first World Series title, the Nationals and their team-record $164 million payroll finished seven games behind the New York Mets.

The morning after the season finale, Rizzo met with 49-year-old Williams at Nationals Park and struck an apologetic tone. The two are close from their time together with the Arizona Diamondbacks in the 2000s. But Rizzo, who also had pressure from dissatisfied ownership, decided it was time for change. Williams, who compiled a 179-145 record and had one year left on his contract, packed his belongings to head home to Arizona on Monday and was not immediately available to comment.

“Matt took it as a professional,” Rizzo said. “He was very thankful of the opportunity to manage this baseball team. He also was thankful of me to give him his first managerial job. He’s obviously very disappointed in the result and the outcome this year.”

Injuries, roster holes and under-performing players undermined the most anticipated season in the Nationals’ 11-season history. But Williams, who was named the 2014 NL manager of the year, also played a role. The Nationals and Rizzo gambled that Williams, a former third-base coach and star third baseman, would succeed despite no previous major league managing experience.

As the Nationals struggled through the season, particularly the second half, more questions about Williams’s leadership and strategy emerged. Rizzo publicly backed Williams, but the tone slightly changed late in the summer when he began saying decisions about 2016 would be made after the season was over.

“Matt had to navigate a lot of rough waters and a lot of trials and tribulations maybe he didn’t have to in the previous season,” Rizzo said.

A Sept. 27 dugout fight between closer Jonathan Papelbon and star outfielder Bryce Harper was the final black eye. Williams insisted he didn’t see Papelbon grab Harper by the neck, and also that nobody told him what happened, highlighting deep issues of oversight and communication. So Williams allowed Papelbon to pitch the following inning, an unfortunate optic that the manager later admitted was his fault.

“There wasn’t any one tipping point that said this was the reason,” Rizzo said. “It was looking at the full body of work and making the judgment that going forward, what’s going to give us the best chance of having the championship-caliber franchise the fan base deserves.”

The Nationals originally hired Williams because of his track record as a player, his organizational and communication skills, and because of their belief that a young manager could grow alongside the team. Williams showed few signs of growth with in-game strategy, though, managing with the same by-the-book style even in must-win situations. His decision to bypass relievers Tyler Clippard and Drew Storen in favor of rookie Aaron Barrett in the deciding Game 4 of the 2014 National League Division Series was the most high-profile example. High-level Nationals officials grew frustrated when the same mistakes were repeated later in 2015.

Players complained privately about Williams’s tense demeanor, his lack of communication and that handling of the bullpen — including warming up relievers without using them in games, an action that wears out arms. Several incidents were detailed in a Post series on the Nationals season, including an unnamed player saying that veteran Jayson Werth ripped a lineup card that omitted him off the wall and confronted Williams, saying, “When exactly do you think you lost this team?”

When Williams finally managed with urgency — inserting Storen or Papelbon into games earlier than their “assigned” innings for the first time in a critical September series against the New York Mets — the plan backfired when players failed to perform.

Williams is the most public face of the Nationals’ wretched season, but he is not alone in their downfall. The roster, already expected to suffer losses through free agency, will undergo further changes. Rizzo, who built the roster and bears the responsibility for the subpar bullpen, is believed to be safe because he has set the Nationals up to be competitive next season and stocked the organization’s minor leagues with young talent. The new manager will likely bring a new style and new coaches.

Knorr; pitching coach Steve McCatty; hitting coach Rick Schu; third base coach Bobby Henley; first base coach Tony Tarasco; defensive coordinator Mark Weidemaier, the only coach Williams brought to Washington; and bullpen coach Matt LeCroy were all let go, although Rizzo said they could return if the new manager wished.

“It’s baseball,” McCatty said. “It’s not fun. They changed the manager and the coaches because it’s way too hard to change the players. When you invest a lot of time with the organization, with the guys and the kids growing up, you’ve got a lot of relationships. It’s never fun. I’ll miss those guys. I’ll miss them a lot.”

The list of experienced managers potentially available includes Dusty Baker, Jim Leyland, Bud Black, Don Wakamatsu and Ron Gardenhire. Knorr, Dave Martinez and Cal Ripken Jr. could be considered as well.

“As we go through the laundry list of things that we look for in our manager and the perfect leader of the ballclub on the field, leadership qualities, knowledge of the games, Xs and Os are all important,” Rizzo said. “Communication in the clubhouse, communication within the coaching staff is vital. Experience is always helpful. It always adds a layer of expertise to someone’s résumé. We feel where we are in our timetable toward winning a championship, we lean toward someone who has managerial experience at the major league level.”