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09/17/12 1:29 AM ET

Davey doesn't want to overuse his relief pitchers

ATLANTA -- While Nationals manager Davey Johnson has no qualms about running out his regular position players every day down the stretch, he said Sunday he's going to remain cautious with how he uses his relievers.

"I don't want to overuse a guy. That's when injuries come in -- and a lack of effectiveness," Johnson said. "I use the bullpen, I lean on it, but I try to spread the work around. But I want them finishing strong.

"Every one of those guys are very valuable. Some of them thrive on a lot of use. With the starters doing what they've been doing, we really haven't had to lean on the 'pen, which is good."

Closer Tyler Clippard leads the team in appearances, with 66 entering Sunday, while Craig Stammen's 81 2/3 innings rank first among Nats relievers. Johnson felt comfortable that he hasn't overused Stammen, and he's often had little need to stretch out fellow long reliever Tom Gorzelanny, instead opting to use him in a more traditional short-relief role.

"They've really adjusted, and I think they're in pretty good shape," Johnson said. "I like where everybody's at, I think."

Espinosa to have MRI on sore left shoulder

ATLANTA -- Nationals second baseman Danny Espinosa will undergo an MRI on Monday afternoon due to a sore left shoulder that has been bothering him for about a week, manager Davey Johnson said after Sunday night's 5-1 loss to the Braves.

Espinosa will likely miss the Nationals' entire series against the Dodgers this week due to the injury, Johnson added.

Johnson said the injury has sapped Espinosa of his strength, to the point that the manager's "little iron man" even admitted it was bothering him toward the end of Sunday's game. Espinosa, who declined to comment through a team spokesman, went 0-for-11 with nine strikeouts and a double-play groundout in the series and was pinch-hit for in the ninth inning.

"I'm a little worried about Espinosa," Johnson said. "He never wants to come out of the game, but I wasn't going to let him hit left-handed, and he said it's even bothering him right-handed, so I'm very concerned about him."

Espinosa, who has played in 144 of Washington's 146 games this season, has recorded only one hit dating back to Sept. 9, the last day of an 11-game homestand. In the 10 games before that at Nationals Park, Espinosa was on fire, hitting .375 with four doubles and two homers.

"Hopefully, it will just be something little and he'll get it checked out," third baseman Ryan Zimmerman said. "Hopefully, it'll be nothing and he'll be ready to go, maybe he'll take a couple days or something, but having the day off [Monday] I'm sure helps."

Davey wants to see LaRoche back with Nats

ATLANTA -- After missing most of last season due to injury and struggling offensively in the limited time he was healthy, Adam LaRoche may have slugged his way into the Nationals' plans for 2013.

LaRoche has a $10 million mutual contract option for next season, and manager Davey Johnson said Sunday there was "no question about it" that he would encourage both sides to pick up that option. LaRoche, who hit his 30th home run Saturday night and has 94 RBIs to go along with a .269/.340/.505 batting line entering Sunday, has previously expressed interest in picking up that option and remaining in Washington.

"I was unhappy to hear that he could test the free-agent market," Johnson said. "We need him back more than we need me back."

In addition to his big offensive numbers, LaRoche has helped bring balance to a lineup that was predominantly right-handed in 2011 and provided a strong, steady defensive presence at first base.

"Obviously, we missed him last year. It's funny what a difference a year makes," Johnson said. "What he's doing is incredible. Offense has been outstanding. He's carried us a lot, had a lot of big hits for us. But the defense is what I really love. His defensive prowess has really gotten us one of the best defensive infields in the league, by far."

Johnson hasn't started pushing LaRoche to stay with the Nationals quite yet, but he noted that he has plenty of time to plead his case, smiling as he kicked around ideas to persuade LaRoche into staying.

"He won't have to give me shots next year in golf or something. That'll hook him in," Johnson said. "He doesn't have to let me play the up tees anymore when we drive. He hits it a long way."

Morse won't play until he can take full BP

ATLANTA -- Michael Morse has been forced to become a spectator for this weekend's series against the Braves, and there's no guarantee he'll be back in the lineup when the Nationals return home Tuesday to play the Dodgers.

Still dealing with pain in his injured left wrist, Morse didn't take batting practice with the team Sunday, although he hoped that a few more days of rest will have him ready to play by Tuesday. Manager Davey Johnson, meanwhile, said Morse won't play unless he's gone through a full batting practice session.

"I'm not counting on anything," Johnson said. "I'm not taking anything for granted. Hope everything gets better. He hasn't been able to take BP, he's not taking it today, so it's bothered him enough."

Johnson said Morse could start Tuesday night if he takes batting practice before the game, but even that "depends on who's pitching." Johnson would prefer that Morse return against a pitcher less inclined to pound the inside of the zone with fastballs.

Johnson has said the past several days that Morse's injury is now more an issue of pain tolerance than anything else, and he noted Sunday that he's willing to be more aggressive with putting Morse in the lineup at this point of the season as long as the doctors say Morse can't further injure himself by playing.

Worth noting

• Johnson said he would try to stay away from using right-handed reliever Ryan Mattheus on Sunday. Mattheus had a rough outing Saturday, recording only one out while giving up a hit, two walks and the game-winning run on a hit batter. Mattheus threw 23 pitches, only nine of them for strikes, and Johnson noted that Mattheus' sinkers were running horizontally too much.

Mattheus expressed some concern after the game that he might have been battling mechanical issues, but Johnson didn't expect Saturday's performance would stick with Mattheus.

• The Nationals lead the Majors in run differential this season, having scored 132 more runs than they have allowed entering Sunday. The Rangers (+122) are second, followed by the Yankees (+95). The Braves (+78) are the only other team in the NL East with a positive run differential.

Adam Berry is a reporter for MLB.com. Follow him on Twitter at @adamdberry. This story was not subject to the approval of Major League Baseball or its clubs.