(Lenny Ignelzi/AP)

Johnson’s words came after Espinosa went 0 for 4 with three strikeouts and a grounder to second in the Nationals’ 5-4 loss, a continuation of his season-long sophomore slump. Espinosa is hitting .186, and his .514 OPS ranks 176th out of 186 qualifying major league players. Only Adam Dunn has struck out more than Espinosa, who has 37 whiffs in 119 plate appearances.

In the spring, Johnson and hitting coach Rick Eckstein instructed Espinosa to swing easy and not try to muscle the ball. Lately, Johnson has said Espinosa was not swinging as aggressively as he’d like. Espinosa seems to be stuck in the middle, guessing at pitches and feeling for the ball. He has swung at and missed 14.9 percent of the pitches he’s seen this year, fifth-most in the majors.

The most troubling aspect of Espinosa’s struggle is that it extends back to last season. After the last all-star break last year, Espinosa hit .227/.310/.352. In his last 94 games, a span of 399 plate appearances, Espinosa has 119 strikeouts, 40 walks and only six home runs. Over that span, more than half a full season, he is hitting .215/.301/.318.

After Espinosa’s excellent first half of last season, at which point he had 15 homers and a .793 OPS, he seemed like the leading candidate for rookie of the year. Through it all, he has remained an athletic, often breathtaking defensive second baseman. But if he cannot improve offensively, Espinosa will soon reach the point at which his performance will determine whether or not he is a major league player.

Espinosa’s slump has been made more acute by the presence of Steve Lombardozzi, who in scattered playing time has hit .300/.373/.350. He has struck out only five times in 70 plate appearances. Like Espinosa, he’s also a switch-hitter.

Johnson, though, will stick with Espinosa for the time being. Espinosa has flashed the potential to hit 25 home runs in a season, and without Jayson Werth and Michael Morse the Nationals need power in their lineup. He is also one of the best defensive second basemen in the majors. Now is not the time to give up on him, or to let him figure it out in the minors — a prospect Espinosa admitted to worrying about. The Nationals need him to produce, and they need to give him a chance.

But if he does not, they will have to ask: When is that time?