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9/1/2013 9:35 P.M. ET

Nationals add callups Krol, Davis, Leon

WASHINGTON -- The Nationals welcomed their first round of September additions on Sunday, recalling relievers Erik Davis and Ian Krol from Triple-A Syracuse and catcher Sandy Leon from Double-A Harrisburg.

Manager Davey Johnson said Friday that the team likely will call up another wave of players, including a third pitcher and three or four more position players, in a few days. Zach Walters will be called up, according to a source, and Jeff Kobernus and Corey Brown are also expected to join the team.

Krol has been a mainstay in the bullpen for much of the season and was optioned to Triple-A less than two weeks ago to make room for Ross Ohlendorf, who was coming off the disabled list. In his short stint at Syracuse, Krol said that he focused on throwing his curveball in the dirt for strikeouts and getting full extension in his delivery. The left-hander also built confidence against Triple-A hitters.

"I got a lot of swing-and-misses down there, and I wasn't getting that up here with my fastball," he said. "Guys were just kind of spitting on it if I was trying to hit the inside part of the plate or whatever. Down there, [it] definitely builds your confidence when you see a guy swing through your pitch and you make a good pitch."

Davis was also a familiar face in the Nationals' clubhouse Sunday after his brief stint with the team in June. The 26-year-old posted a 6.23 ERA in five appearances with the Nationals before returning to Syracuse, where he has mostly pitched in late innings.

Davis noticed that he was approaching the mound differently depending on the inning and situation in the game. He said that his primary focus over the past two months has been to bring his ninth-inning approach to each of his appearances.

"It's taking that same approach, that same kind of fire, into every outing, no matter what the scoreboard says," the right-hander said. "Hopefully this month, I can just continue to refine my approach and hopefully put myself in a good spot for next year."

The biggest surprise of the group was the 24-year-old Leon, a reliable defensive catcher who hit .177 in 95 games at Double-A Harrisburg this season. Leon, who is ranked as the Nationals' No. 15 prospect, admitted that he has been struggling at the plate recently and said that he was looking forward to working with hitting coach Rick Schu. He said that his troubles have been more mental than mechanical.

"I think too aggressive, sometimes too aggressive at pitches and you've got to be smart, too," Leon said. "So I think just to calm down in the game and just relax and see what happens."

Johnson said Friday that it is important to have an emphasis on this season but also an eye on the future. All three players understand that the final month could serve as an audition for next season and beyond.

"I've learned so much since I've been up here. Being around guys that have been doing it for three, four years helps so much more," Krol said. "So I definitely want to finish strong, want to take whatever happens up here in the next month and bring it into the offseason, think about it and work on some things."

Schu making an impact as Nats' hitting coach

WASHINGTON -- It's been a little more than a month since the Nationals dismissed hitting coach Rick Eckstein and brought in Rick Schu, and at least on paper, the change appears to have had an effect.

In 99 games with Eckstein this season, the Nationals hit .241 and scored 3.71 runs per game. In 36 games with Schu before Sunday, they had hit .273 and averaged 4.5 runs per game. The Nationals have also struck out less frequently (once per every 5.1 at-bats instead of once per every 4.3 at-bats) since Eckstein's departure.

While the Nationals have also had a healthier lineup since Schu's arrival, the new hitting coach hopes that he has made a difference.

"Hopefully, because we've been doing good," Schu said, laughing. "This team got kind of labeled as the best team in baseball, and I think everybody put so much pressure on themselves. I just tried to come in here and get guys to not try so hard, be more of a team ... move runners, drive that runner in from third with less than two [outs], things like that, more team-oriented stuff."

While Eckstein liked to see players pull the ball, Schu said that he wants them to use the whole field. Otherwise, Schu said that he has not made any drastic changes. He works with each hitter individually to build upon what they do well and said the only player that he hasn't had many conversations with is shortstop Ian Desmond.

"He's been kind of Davey's guy," Schu said. "He's been messed with so much, he's a guy you kind of just have to let him play."

When Eckstein was dismissed in late July, some Nationals said that a new hitting coach would not make much of a difference. But for Denard Span, who is in the midst of a career-best 14-game hitting streak, Schu's arrival was needed.

"He's made a big difference. I've got to give him credit. Definitely him and [first-base coach] Tony Tarasco," Span said. "Since Schu moved into the new position, he just brought me back to basic stuff -- staying through the ball, staying balanced, having rhythm, things that I've done to get me to this point that I got away from."

Worth noting

• After winning 49 of their 58 regular-season games, the Gulf Coast League Nationals defeated the GCL Red Sox, 7-2, on Sunday to win the league's championship series.

• After missing 28 games this season with a strained hamstring, Jayson Werth now has enough plate appearances to qualify for the National League leaderboard. His .322 batting average ranked third in the league entering Sunday.

Tom Schad is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.