Pat Corrales was the team's bench coach, while Tim Tolman and Jerry Morales were the third-base and first-base coaches, respectively. Bullpen coach Rick Aponte and hitting coach Lenny Harris also will not be back next season.
Washington also dismissed conditioning coordinator Kazuhiko Tomooka and video coordinator Tom Yost.
The reason the club kept St. Claire is because it likes the way he works with young pitchers such as John Lannan and Collin Balester.
All the coaches were in uniform for Sunday's 8-3 loss to the Phillies at Citizens Bank Park.
"There are a lot of changes that we need to make to get where we want to get to. We are going to start 2009 [on Monday] morning," general manager Jim Bowden said. "There are areas in our operation where we want to go about it a different way and in a different direction."
According to Acta, the coaches took the dismissals professionally. However, the skipper took it hard after he and Bowden told them the news. In fact, the coaches had to pump Acta up before the game started.
"It's a very tough day for me." Acta said. "Obviously, I'm new at this. This is my second year managing. I'm a blessed individual that hasn't had any bad news in my life, except for the death of my older brother.
"I have nothing but nice things to say about my coaches. They did a great job for me the last two years. They worked their butts off for me and these kids. I wish them nothing but the best."
Of all the coaches let go, Harris and Tolman were most often on the hot seat. Harris was in trouble because of the team's lack of offense this year. Besides being blanked 20 times this season, the Nationals rank near the bottom in almost every offensive category.
Harris often said he didn't have the lineup he hoped to have because a lot of the planned starters, such as Nick Johnson and Ryan Zimmerman, were on the disabled list.
"Last year, everything was good, because I had all my hitters," Harris said. "It was a tough job for me this year with a lot of young guys. It was hard for me to prepare them, because each and every day, you had to go over the same situation -- what a pitcher throws and what he likes to throw. They pretty much were not use to that. It was a learning thing for them.
"What hurt me was my big guns went down early and that hurt me a lot. ... That's something I have to learn, too, just in case I get a whole bunch of young guys at one time."
As for Tolman, he was often criticized for having runners thrown out at the plate last year, but he improved in that area this season. A lot of baseball people believe his strength was as a bench coach.
"Baseball is not fair. It has been this way for over 100 years," Tolman said. "But when a team struggles, it will make changes. That's baseball. I leave here with my head held high. I feel like I did a good job at third. I got better at it."
Corrales has worked in baseball for 50 years and he made an immediate impact on catcher Jesus Flores, who quickly became a quality catcher at the age of 23. Corrales said he is not sure what he is going to do next season.
"I have to talk to my wife," he said. "I have to think it over. I'll go from there."
There was no immediate word on who the Nationals will bring in to replace the coaches. With Rick Eckstein promoted to the big leagues in late August, there is speculation that he will be the new hitting coach, but the Nationals declined to comment.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.