WASHINGTON -- Nationals third baseman Ryan Zimmerman, on the disabled list because of an abdominal strain, is scheduled to play in his first extended spring game in Viera, Fla., this week.

Manager Jim Riggleman said that Zimmerman was feeling uncomfortable when it came to throwing the baseball, but he is still going to play third base in the game.

No timetable was announced as to when Zimmerman will start his a rehab assignment, but he is expected to play in a big league game in mid-June.

Zimmerman's absence is one of the reasons the Nationals are ranked near the bottom of the Majors in offense. But unless they can make a trade involving catcher Ivan Rodriguez and/or reliever Todd Coffey, the Nationals aren't expected to make any changes before Zimmerman returns.

The team doesn't have anyone in Double- or Triple-A who could make an impact offensively right now. It was already reported that first baseman Chris Marrero was not on the radar to get a promotion to the big leagues. He has started hitting in the last couple of weeks, but he most likely will not be in the big leagues until September.

Asked if he had problems putting together a lineup, Riggleman said, "I really see our offense coming together. I think in the last couple of weeks, you see what Mike Morse and Laynce Nix have done. ... You see what Danny Espinosa has done.

"We have a few guys who have yet to get it going offensively, but I feel like we are going to get it together as a team offensively. In the meantime, we have to win ballgames in some manner."

Riggleman encourages Nats in team meeting

WASHINGTON -- An hour before his team played the Phillies on Tuesday night, Nationals manager Jim Riggleman held a meeting with the players to tell them to forget about the first third of the season and stay positive. Entering the game, the Nationals were 22-31, 11 1/2 games behind Philadelphia.

While the Nationals played hard on the field, Riggleman felt there wasn't any energy in the clubhouse after losses. According to a baseball source, Riggleman felt the offense -- which is batting .233, ranked near the bottom in the Major Leagues -- played a role for the players being down in the clubhouse.

"[Riggleman] felt [the lack of hitting] was dragging some people down," the source said. "He said, 'Let's put that first third of the season behind us. Let's get after it. Let's not get down about the first third of the season. We are going to take off offensively.' It was a very positive tone."

The source also said Riggleman wasn't the only person who spoke. Some of the coaches and one player contributed, but the source declined to say who said what.

The meeting appeared to pay dividends. The offense came to life as the Nationals pounded the Phillies, 10-2, at Nationals Park. Second baseman Danny Espinosa was the hitting hero, with two home runs and four RBIs as Phillies left-hander Cliff Lee allowed six runs in 5 1/3 innings.

"You have to pick your spots, and I think Jim found it prudent to say what he had on his mind. We came out and banged the ball around the yard. Obviously it was good," right fielder Jayson Werth said. "Obviously, we are going through some hard times, some growing pains. It's not to be unexpected.

"I don't think anyone expected us to come out and blow the doors off this year, especially when we lose Zim [Ryan Zimmerman] and [Adam] LaRoche. At the same time, you have to stay positive believe what you are doing. ... It's good to take a step back, take a deep breath and look at the big picture a little bit. That's what we did tonight. We took the weight off our shoulders a little bit. We went out there and had a good game. Hopefully we could build on it."

Nats target center fielder, leadoff man

WASHINGTON -- The Nationals are looking to trade for a center fielder and a leadoff hitter, according to a baseball source, who also said the club is willing to overpay to get players at those specific positions.

Some members in the organization don't think Roger Bernadina is a center fielder. They feel he belongs in one of the corner spots. Bernadina has been getting most of the playing time in center field lately.

Rick Ankiel, the team's other center fielder, has not been productive, hitting .214, with a homer and seven RBIs.

The Nationals are also not getting enough production from the leadoff spot. Entering Tuesday's game against the Phillies, Washington's leadoff hitters are hitting a combined .195, with a .250 on-base percentage.

If the Nats look to trade catcher Ivan Rodriguez or reliever Todd Coffey, it wouldn't be surprising if they ask for a center fielder in return.

Nationals' prospect Moore nabs weekly honors

WASHINGTON -- Double-A Harrisburg first baseman Tyler Moore was named Player of the Week in the Eastern League for the period of May 23-29.

Moore hit .448 (13-for-29), with three home runs, seven RBIs and a .897 slugging percentage in eight games during the week. Moore, 24, posted five multihit games and recorded at least one RBI in six of the eight games.

In 2010, Moore was named the Nationals' Minor League Player of the Year and the Carolina League's MVP after hitting .269, with 31 homers and 111 RBIs in 129 games for Class A Potomac. Moore was selected by the Nationals in the 16th round of the 2008 First-Year Player Draft.