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04/11/12 1:19 AM ET

Setback means Morse will miss Nats' opener

NEW YORK -- Nationals outfielder Michael Morse suffered a setback Monday while playing for Class A Hagerstown, leaving the game in the seventh inning against Lexington because of a strained lat (back) muscle.

The news means that Morse will not be ready for the Nationals' home opener against the Reds on Thursday. Morse can swing the bat without any problems, but he continues to feel discomfort while throwing the baseball. In fact, Morse had problems throwing the ball back to shortstop Jason Martinson in yesterday's game.

According to Nationals manager Davey Johnson, Morse will get further test in the upcoming days. Johnson is not sure when Morse will return to action.

"I was hoping that it was just the cold weather, but he has also been examined by our doctor," Johnson said. "[He is] concerned about it and there will be further tests on him. Hopefully, it's nothing that serious. I don't like the fact he was swinging the bat well and he took himself out of the game because his arm was bothering him."

Aggressive mindset translates for Werth at plate

NEW YORK -- Prior to Tuesday's game against the Mets, Nationals hitting coach Rick Eckstein said he wasn't worried about Jayson Werth's swing, even though the latter was 1-for-14 with seven strikeouts.

Eckstein pointed that Werth had good at-bats, including key walks, during the three-game series against the Cubs. Entering the three-game contest against the Mets, Eckstein had to remind Werth that he was swinging the bat well and continue to have an aggressive mindset at the plate.

Werth followed through on that in a 6-2 victory over the Mets on Tuesday, going 4-for-5 with two RBIs. He raised his batting average to .263.

Prior to the game, Werth had a conversation with manager Davey Johnson, who told him to be himself and express his talent. Werth did. He ended up having his best game as a member of the Nationals.

"We had a good talk before the game and he was in a good frame of mind," Johnson said about Werth. "He is so driven to do so well, sometimes that can get in your way."

Werth said he was more focused on being relaxed at the plate.

"Looking back, really, that is something I have done in the past and has been a focus. Hopefully, I will continue to do that," Werth said.

Espinosa given precautionary rest by Nats

NEW YORK -- Nationals manager Davey Johnson decided to give second baseman Danny Espinosa the day off on Tuesday after Espinosa collided with Mets shortstop Ruben Tejada in the ninth inning the previous night. Stephen Lombardozzi received the start at second base.

"With all [injuries] going on, [Espinosa] got hit pretty good," Johnson said. "I didn't want him to go out there with a stiff neck or being woozy. Based on last year, I hardly ever took him out of a game. But I'm going to be cautious."

Tejada came to the plate and bunted the ball toward reliever Henry Rodriguez, who threw the ball past Espinosa for a two-base error. During the play, Tejada and Espinosa collided at first base. Espinosa was dazed, but prevented Michael Baxter from scoring with a great throw to third base.

The Mets would win the game, 4-3, on a walk-off single by Daniel Murphy. After the game, Espinosa went to see the doctor, who found nothing wrong with him. Espinosa was also able to sleep without any problems.

"I feel great. I went to the doctors after we got done. They wanted to make sure I was all right," Espinosa said. "I didn't have any symptoms. ... I went to sleep and I didn't feel nauseous. Nothing seemed wrong this morning. I feel good."

Worth noting

• After suffering a leg injury in an 8-7 victory over the Lexington on Monday, Class A Hagerstown outfielder Brian Goodwin is listed as day to day, but the Nationals have not ruled out putting him on the 7-day disabled list.

• Third baseman Anthony Rendon suffered a badly sprained left ankle while running the bases in a 7-2 loss to Lynchburg on Saturday. X-rays were negative, and he was placed on the 7-day disabled list on Monday.

Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.