VIERA, Fla. -- In his brief time with the Nationals in 2006, reliever Chris Schroder struck out 39 batters in 28 1/3 innings, however, he had an ERA over six. It also didn't help that he relied too heavily on his fastball.

What did Schroder do to get better for the 2007 season?

He spent two weeks in the Dominican Republic with Jose Rijo, the special assistant to general manager Jim Bowden, to work on his slider and changeup.

"I'm trying to get more depth on the slider. That has been probably my third best pitch for the most part," Schroder said. "The fastball has always been good. That's how I get my strikeouts, always up in the zone. Sometimes I don't always have good control. It's probably because of the quality of [his] secondary pitches."

On Saturday, Rijo continued to tutor Schroder. Following his bullpen session, Rijo told the right-hander that he had his hands up too high during the stretch and that he needed to get them near the chest area.

Front-office change: The Nats announced that assistant general manager Bob Boone has accepted the resignation of Andy Dunn, who was the club's director of player development.

Boone and the remainder of the baseball operations staff will assume all of Dunn's duties. Further restructuring within the Nationals' player development department will be announced at a later date.

When reached by phone, Boone declined to say why Dunn resigned.

"I respect Andy and we'll move forward and build the best player development program in baseball," Boone said.

Meeting of the minds: According to a baseball source outside of the organization, the Nats are still talking to free-agent second baseman Ronnie Belliard's representatives.

If Belliard signs with Washington, he will join the team immediately, the source said on Saturday. However, Belliard would have to take a huge pay cut -- he made $4 million in '06, but might have to settle for $700,000 to $1 million.

The best that he can be: Ryan Zimmerman, arguably the best defensive third baseman in baseball, said recently that he made some silly errors in '06.

Zimmerman is working with Barry Larkin, the special advisor to the general manager, twice a week on his footwork at Space Coast Stadium.

In practice, the young third baseman was seen on his knees fielding ground balls, working on his throws at third and shortstop and also turning the double play at second base.

"There were four or five errors I could have avoided if I used my feet a little more," Zimmerman said. "We were concentrating on not ever stopping my feet. Just getting my feel planted. It's also going to save my arm a lot more if I get all of my momentum toward first base."

Future plans: Manager Manny Acta announced that Kory Casto will get most of his Spring Training at-bats as a third baseman. Acta said that Casto wouldn't have received many at-bats playing in left field, because Ryan Church, Chris Snelling and Alex Escobar are fighting for time there.

The Nats still look as Casto as their future left fielder, and he will work at the position during batting practice.

"When [Zimmerman] is out of the game, Casto is the guy. We have enough guys in left field," Acta said. "We want to get Casto as many at-bats as possible, so we can take a good look at him and make a decision at the end of camp."

According to Casto, assistant general manager Bob Boone informed him of the team's plans a few weeks ago and believed it was a good idea.

"Whatever it takes to get at-bats, I'm going to do that," Casto said. "It will give them a better feel on what I can do [with the bat]."

He's here: Infielder Tony Womack arrived in camp and said that he signed with Washington, because he wanted to help the team win.

Womack, 37, had his best season under hitting coach Mitchell Page in 2004, when both were with the Cardinals. That season, Womack hit a career-high .304 with five home runs and 38 RBIs, but he declined to say what the secret of his success was with Page.

In case you're wondering: Juan Brito, Jesus Colome, Anastacio Martinez, Luis Martinez, Arnie Munoz, Felix Diaz and Edward Valdez arrived in Viera on Friday and participated in their first workouts Saturday morning. All six players had visa problems early in the week.

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