"I don't feel the injury at all [while throwing]," said Ryan Mattheus.

VIERA, Fla. -- Reliever Ryan Mattheus, who hasn't pitched in a game because of inflammation in his chest, played catch from 60 feet the past two days and hopes to start having bullpen sessions within a week.

After at least two such sessions, Mattheus will probably throw batting practice. He does not know when he will pitch in a game.

"I don't feel the injury in there at all [while throwing]. That's very positive," Mattheus said. "There was still a little soreness in there when I lifted for the first time."

Walters begins seeing work at second base

Zach Walters had been slated to start at second Wednesday.

VIERA, Fla. -- Before Tuesday, infielder Zach Walters hadn't played second base since he joined the Nationals in 2011. Walters, who plays shortstop and third base, is trying to make the 25-man roster as a backup infielder, and was told to begin working at second on Tuesday.

Walters was scheduled to start to against the Mets at second base Wednesday, but he was a late scratch because of flu-like symptoms. Mike Fontenot started in Walters' place.

"He is really sick," manager Matt Williams said about Walters. "He wouldn't tell anybody. We looked at him, and he didn't look too good. We asked him, and he reluctantly said he didn't feel well."

Walters entered Wednesday as one of Washington's hottest hitters this spring, going 6-for-7 (.857) with a homer and three RBIs.

"We want to make sure he gets some time [at second base]," Williams said. "It may be limited, with the amount that he plays over there. He plays short, he plays third, certainly. He'll get some time at second. He stayed back [Tuesday] and got some work done at second base. You'll never know when he will be asked to play there or not. We have to make sure he is comfortable."

Meanwhile, outfielder Steven Souza was working at first base, and he looked comfortable at the position.

Although he is known as an outfielder, Souza started his professional career as an infielder. He started out as a third baseman, saw some time at shortstop, and played 117 games at first for Class A Potomac in 2011.

"I'm pretty comfortable. I grew up as an infielder. So anywhere in the infield, I'm getting my feet underneath me. I love it. It's fun," Souza said. "I will do anything to help the team out if they need someone."

Desmond working on opposite-field approach

Ian Desmond has been focused on hitting to right field.

VIERA, Fla. -- Nationals shortstop Ian Desmond started Wednesday's 11-5 victory over the Mets and went 1-for-2, including an opposite-field home run in the third inning off left-hander Adam Kolarek.

Desmond is off to a fast start, going 4-for-10 with two home runs and three RBIs. Desmond has been working a lot with hitting coach Rick Schu, and the 2012 and '13 National League Silver Slugger Award winner is making an effort to hit the ball to the opposite field on a regular basis.

"He is doing what he wants to do. He is up there with an approach, and it's early," manager Matt Williams said. "He wants to be competitive on the other side of the diamond, just like today. He wants to be able to drive balls in that gap and backspin balls to the opposite side. He is working on that during batting practice, in his cage work. His work ethic is fantastic. He is right in line with what he wants to do."

Gio feeling strong after outing against Mets

Gio Gonzalez tossed two shutout innings Wednesday.

VIERA, Fla. -- Nationals left-hander Gio Gonzalez started his first game of the spring and looked sharp in an 11-5 victory over the Mets on Wednesday. He pitched two shutout innings and allowed a hit.

"My arm feels right where I wanted it to be. I feel strong, I feel ready. This team looks great. Our guys look alive," Gonzalez said.

In his next start, Gonzalez wants to go at least five innings and throw more first-pitch strikes. Gonzalez reiterated that he wants to do the little things to help the team win games. For example, he wants to work on his pickoff move and covering first base, which was a serious problem last year.

"There are a bunch of things I want to work on during Spring Training this year. Hopefully, I'll have enough time to do it," Gonzalez said.

Williams pleased with Espinosa's approach

Danny Espinosa has just one strikeout in 10 at-bats this spring.

VIERA, Fla. -- Although infielder Danny Espinosa is 0-for-10 to start the spring, manager Matt Williams is satisfied with his approach at the plate.

Williams is not concerned that Espinosa is putting too much pressure on himself. In fact, he and his coaching staff have talked to Espinosa about what he has done.

"The at-bats he has taken so far are really good," Williams said. "He doesn't have any hits in 10 at-bats, but it really doesn't mean anything. He has pounded the ball pretty good left-handed. He has had a couple of balls taken from him in the infield. He hit a ball hard to center field. If those drop, now he is hitting .400.

"In those limited at-bats, you can't make a determination. What we see is him having good at-bats and putting the ball in play hard. It's exactly where he wants to be. I told him every day, 'Stay right there. That's exactly what you want.' The results aren't there, but they really don't mean [anything] right now anyway. The fact that he has taken good at-bats is important. That's all we look at."

Espinosa is coming off the worst season of his career, and he spent most of it at Triple-A Syracuse. He must cut down on his strikeouts, and entering Wednesday he had just one in those 10 at-bats, which a good sign.

Espinosa was not in Wednesday's lineup against the Mets.

Worth noting

Michael Gonzalez, who signed a Minor League deal with an invitation to Spring Training on Tuesday, is expected to report on Wednesday.

• Right-hander Ross Ohlendorf is expected to pitch on Thursday night against the Braves. He hasn't appeared in a game thus far because of a sore finger. Earlier in the spring, he had a problem with his side.

• After the team's 11-5 victory over the Mets, Williams and his coaching staff discussed the first round of cuts. Before making the announcement, however, the team has to get through a split-squad game on Saturday and observe the health of the players. Several of them have flu-like symptoms.