updated 12:24 p.m. ET July 13, 2009

So much for the plan to have Manny Acta’s patient optimism lead the Washington Nationals out of the doldrums. The abysmal won-loss record became too much to stomach, costing him his job at the All-Star break and adding another layer of instability to the worst team in baseball.

Acta was fired after the team reached the unofficial halfway mark of the season with a majors-worst 26-61 record, on pace to clear the 100-loss mark for the second consecutive year. Acting general manager Mike Rizzo — himself an interim placeholder — announced Acta’s dismissal Monday morning.

“We feel that the team has underachieved,” Rizzo said. “We feel we have a better ballclub than we’ve shown on the field. ... We feel with a different voice and possibly a different feel in the clubhouse that we can have a more successful second half of the season.”

Acta was informed Sunday night after the team returned home following a 5-0 loss at Houston, Washington’s seventh in 10 games. Bench coach Jim Riggleman, who has a 522-652 record over nine seasons managing the Padres, Cubs and Mariners, was named the interim replacement — which means the Nationals now have both a GM and a manager with a temporary label next to their names.

“I’m very uncomfortable with that,” team president Stan Kasten said. “I’ve strived my whole career valuing stability and consistency, and I want to get to that here. We’re not there yet. I think we’re working toward that. Sometimes you encounter these unfortunate, unforeseen bumps in the road.”

Acta joins Colorado’s Clint Hurdle and Arizona’s Bob Melvin as major league managers who have been fired this season.

“It was a great learning experience, I have no regrets,” Acta said in a statement released by the team. “As I move forward, I wish the Nationals all the best. I was very fortunate to work with and meet a lot of wonderful people while here.”

Acta was 158-252 over 2½ seasons in his first managerial job. The team’s winning percentage dropped progressively from Year 1 until now, although his record had much to do with the talent — or lack thereof — assembled for him by the front office. The Nationals opened this season without anything close to a reliable bullpen and fielded a lineup with numerous defensive liabilities. For a while, the starting pitching rotation consisted of four rookies and one second-year player.

Not surprisingly, the Nationals’ 5.21 ERA is by far the worst in the National League, and their 82 errors are the most in baseball. The team’s only All-Star, third baseman Ryan Zimmerman, already has 12 errors, and the strain of endless losing began to show among many players in the form of fundamental mistakes in the field and at the plate.

“I’m not satisfied with the way we play the game at times,” Rizzo said. “We don’t execute nearly as often as I expect them too. But the effort as far as the hustle and preparation is there — the consistency of the effort and the hustle needs work. The way we fundamentally play the game needs a lot of work.”

Acta always remained upbeat, preaching patience and emphasizing the importance of keeping an even keel — so much so that some wondered whether he needed to show more fire and perhaps be more critical publicly when his players made mistakes. Rizzo said Acta’s style made it more difficult for the team to recover from an 0-7 start.

“The response was from a slow start out of the gates, and then getting into a hole that they felt they couldn’t get out of, I think that was a big part of it,” Rizzo said. “And sometimes the even-keel-ness plays into that by not being a little more vocal, a little bit more hard-edged.”

By contrast, Rizzo also called Riggleman “a tough disciplinarian” who is “going to show the young players that this is a difficult game to play.” Rizzo said Riggleman, who will not hold his first news conference until Wednesday, “will be a candidate to be the long-term answer” as manager.

Acta’s firing is only the latest example of the constant upheaval surrounding the Nationals since Kasten and local developer Ted Lerner took over the club during the 2006 season — a sale that was supposed to finally bring a semblance of normalcy to the franchise.

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When Acta was hired in November 2006, he was 37, and no manager in the majors was younger. In his first season, Washington finished 73-89, fourth in the NL East but a two-win improvement over 2006 and better than was expected. Acta even received votes for NL Manager of the Year.

But the team took a step backward in 2008, going 59-102 for a .366 winning percentage, the worst in the major leagues. And there was even more regression this season — the Nationals’ .299 winning percentage is far lower than any other team. Every coach except pitching coach Randy St. Claire was fired at the end of the season, and St. Claire was dismissed at the beginning of June.

From the outset of spring training in February, Acta called the current team the most talented he’s had, but the Nationals never came close to approaching .500. Even so, Rizzo and Kasten took a page out of Acta’s book on Monday and were flush with optimism about the team’s young talent base.

“I do think we’re very close to realizing the fruits of three hard years of effort,” Kasten said.

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