John Lannan (Carolyn Kaster/AP)

On the first day of expanded rosters, the Nationals, as expected, made only a handful of moves. They called up starter John Lannan, outfielder Eury Perez and catcher Sandy Leon, and activated Mark DeRosa from the disabled list. It wasn’t a slew of a new faces and that’s by design.

“We have what we need here without any reinforcements,” Nationals Manager Davey Johnson said. “This gives some other guys some big league time, some big league experience. It gives them a chance to get them in games. But I’m not worried about getting them in games and getting playing time.”

Lannan, 27, will move to the bullpen before later taking Stephen Strasburg’s spot in the rotation when he is soon shutdown. For now, Johnson will try to keep him on his regular schedule and have him throw a bullpen session on Sunday and pitch out of the bullpen in the meantime.

Perez, a 22 year-old speedster from Class AAA Syracuse, will be used sparingly to pinch-hit, leadoff an inning in a double switch, maybe play center field, Johnson said. (He would take over starter Edwin Jackson’s secondary role as the team’s de facto pinch runner.) Leon, 23, who played in 10 games for the Nationals this season, will serve as the Nationals third catcher. “That always gives you another bat,” Johnson said. “And catchers that are playing, gives him a chance to pinch-hit.”

Johnson wants to keep his regular players fresh so, beyond Lannan, the September call-ups may see limited playing time. (An upcoming second wave of call-ups would likely include Corey Brown and reliever Christian Garcia.) In years past, the Nationals were able to evaluate the reinforcements with significant playing time. But deep in the pennant race, the situation is different.

In fact, it may be a factor more for their remaining opponents, such as the Chicago Cubs, Milwaukee Brewers or Miami Marlins, who are deeper out of playoff contention. The Nationals will be facing players they know little about and have the added motivation of trying to earn playing time. In essence, the Nationals may be facing the top minor league prospects of other teams.

“Last year for us, I got to pitch [Brad] Peacock and [Tommy] Milone,” Johnson said. “[Lombardozzi] got to play. It’s good for the organization, good for evaluating. I mean, there are some negatives. You go in to play a club like Chicago. They’ll be running them out of the woodwork and you don’t really know who they are. Sometimes those game can be a little tougher.”

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