PITTSBURGH -- According to manager Davey Johnson, Nationals first baseman Chris Marrero is having problems with his right shoulder and left hamstring.

Johnson believes Marrero is another month or two from playing in a Major League game. Marrero tore his left hamstring while playing for the Licey Tigers in the Dominican Winter League this past offseason.

Marrero, who is considered a backup first baseman, hurt the hamstring stretching for a thrown ball.

Johnson believes the shoulder problems were caused by the fact that he was overaggressive during his rehab.

"I think the shoulder stuff is coming from a lot of hitting, throwing and a little weight work," Johnson said. "I'm not as concerned about some of the medical reports on the shoulder."

LaRoche doesn't let boo birds get to him

PITTSBURGH -- Nationals first baseman Adam LaRoche played two-plus seasons for the Pirates, and received a lot of boos from Pirates fans during the three-game series.

The boos didn't seem to bother LaRoche, as he went 4-for-8 with two home runs, including the game-deciding homer in Washington's 4-2 victory on Thursday night.

It wasn't like LaRoche was a bad player in Pittsburgh. His best year for the Pirates came in 2007, when he hit .272 with 21 home runs and 88 RBIs.

Asked why he was booed throughout the series, LaRoche said: "I don't think I'm a fan favorite here, so that was nice to hear them boo a little louder on a couple of those shots. ... I've received the boos ever since I left. I'm kind of used to it here. I don' know what it is. I guess it's them welcoming me back."

Johnson holds team meeting before finale

PITTSBURGH -- A day after watching his team lose its third straight game, Nationals manager Davey Johnson held a team meeting around 4:30 p.m. ET on Thursday. The meeting lasted about 10 minutes.

The meeting came after the Nationals left 10 runners on base and had runners in scoring position with less than two outs in the final two innings of a 4-2 loss to the Pirates.

"[The meeting] probably wasn't needed," Johnson said. "I just wanted to take a little air out of the bubble. Maybe it was more for me than them."

Johnson told his players that he was not in a panic mode and that he still believed in them. Johnson proved it by not making massive changes to the lineup. The only significant change was that Johnson placed Roger Bernadina in the second spot of the lineup, and Bryce Harper went from second to the fifth spot in the lineup. Johnson is looking for more pop in the middle of the order.

"Yesterday's loss was really tough. It was a game that I really liked the matchups we had late in the game. I thought certain guys were pressing," Johnson said. "I wanted to let them know that I'm with them 100 percent. I know we are going to get better as the season goes on.

"I appreciate the effort we have so far. I don't fall victim to the new era of tweeting, Facebook, all the comments and all the help [the fans] want to give you on how to manage a ballclub. I have confidence in everyone on this ballclub. I expect us to get it right."

Johnson also had individual meetings with Harper and second baseman Danny Espinosa. With Harper, Johnson felt the 19-year-old rookie popped out in the ninth inning of Thursday's game because he expanded the strike zone. Johnson felt Harper didn't swing at a strike during the at-bat.

Entering Thursday's action against the Pirates, Espinosa was off to a slow start, going 20-for-106 (.189) without much power. Johnson considered giving Espinosa the day off on Thursday and replacing him with Steve Lombardozzi, who has been consistent with the bat.

"Lombo would enjoy the opportunity to go out and play second base. [Espinosa] said, 'I feel better. I've been a little confused.' I had a great conversation with him," Johnson said. "It was nothing more than 'I will give you every opportunity to do things you are capable of. We need you.'"

DeRosa tweaks shoulder cheering for Harper

PITTSBURGH -- Infielder/outfielder Mark DeRosa, who is on disabled list because of a left oblique strain, suffered a minor setback during Sunday's 9-3 loss to the Phillies, according to manager Davey Johnson.

DeRosa injured his right shoulder while cheering for Bryce Harper, who stole home in the first inning of Sunday's game. It's not known how DeRosa hurt the shoulder.

"I don't know if that set back the rehab or not," Johnson said. "It was a spur-of-the-moment thing," Johnson said.