That’s a limited sample size, but it has struck a blow to Espinosa’s rookie of the year candidacy. Espinosa, thanks largely to consistently outstanding defense, still leads all major league rookies with 3.0 wins above replacement, the catch-all metric used by to measure a player’s value. But Espinosa’s slash line for the season has fallen to .223/.311/.414, numbers that voters will likely punish him for.

Espinosa has run into some bad luck in the second half, typified by last night. In his fourth at-bats last night, he dropped down a drag bunt that pitcher Matt Thornton fielded and flipped with his glove only, a play that made SportsCenter’s Top 10. In his last at-bat, he smoked a line drive up the middle, which the second baseman snared. His batting average on balls in play in the second half is .200, about 100 points below league average.

Espinosa, though, has also not put the ball in play all that frequently. Espinosa’s lone blemish in the first half, as he became the favorite to win rookie of the year, was his high strikeout rate. That’s actually gotten worse in the second half, from one strikeout every 3.9 at-bats to one every three at-bats.

Espinosa’s home run rate has plummeted, too. He’s got one homer in 19 games and 77 at-bats since the all-star break, down from the 16 he hit in the first half in 326 at-bats, or one homer every 20.4 chances.

Pitchers could be taking advantage of Espinosa’s penchant for hacking at pitches out of the strike zone. He has swung at 30.6 percent of pitches thrown out of the strike zone, according to date compiled by FanGraphs.

“He’s still learning about himself as a hitter,” Manager Davey Johnson said. “When you really get to be a quality big league hitter, you know pretty much what they’re trying to do to you from the right side and the left side, and you know where your happy zone is. Right now, I think he’s expanding his zone. He’ll swing at high pitches, low pitches. He really isn’t centered on looking for things that he likes, and that comes with maturity.”

Even as Espinosa has struggled lately, he has remained in the lineup. Espinosa has played in all 111 games this season, the only Nationals player who can say, and is adamant he wants to play in all 162. Johnson will let him.

“He’s such an exciting player, he’s in such great shape,” Johnson said. “He doesn’t look tired to me. I talked to him a couple times about giving him a day off, and he didn’t really have a smiling face after that conversation. I like watching him.”

Espinosa and the Nationals can take comfort not only in Espinosa’s dreary average on balls in play, which is due for a correction, but also how he began the season. Espinosa was hitting .193 on May 15, and for the remainder of the first half he punched up a an .893 OPS.