The first professional sign of struggle from Bryce Harper — the first indication that major league baseball cannot be conquered at age 19 — has drawn from him a new feature: defiance.

It doesn’t come from anger, but rather self-assurance. He ignores the numbers and says he is not in a slump. He mentioned that he felt “all over the place” at the plate last week, and later he was asked to further explain what he meant. “I feel good now,” he said. “I don’t really want to talk about that.”

And still, over the next week of games Harper played for the Washington Nationals, he could not improve his statistics. He has instead continued to come to grips with, and try to extricate himself from, his first prolonged struggle in the majors. Harper’s initial two months made him an all-star and led to favorable comparisons to the best seasons ever by a teenager. His third month has reduced his season, in sum, to league average and made him confront baseball’s defining challenge. He has had to face failure.

Harper’s unassailable confidence remains. When he exploded into the majors, he shrugged and insisted he could play better. As his batting average has dwindled, he has calmly suggested he is just fine, not the least bit frustrated. Every time questions are raised, he will not question himself.

“I don’t change anything,” Harper said. “I don’t try to change anything. My swing has worked since I was 7 or 8 years old. There’s nothing to be changed. It’s just things that happen. It’s the process of trying to stay within yourself and trying to do what you’ve been doing your whole life. You know, not chase their pitches, get that one pitch in your zone and hit it.”

The difficulty of getting that one pitch became an issue last week in Houston. Harper struck out looking on two controversial calls by home plate umpire Angel Hernandez. Manager Davey Johnson gave Harper the next day off to “let him take a step back.” Johnson sensed frustration. Harper said that was not the case.

“I’m not frustrated at all,” Harper said. “I haven’t been frustrated all year. The only thing I’m frustrated about is the other 24 guys I let down.”

He also felt wounded by calls against him. He said opposing pitchers had been getting strike calls “two or three inches off the plate,” and had been taking advantage. Harper responded by not changing. He will not expand his strike zone. He will not swing at pitches he perceives to be balls, even if umpires keep calling them strikes.

“I’m going to stick with my plan as best I can,” Harper said. “I think I should have 100 walks. I think if I’m looking at pitches and trying to find that mistake, I think when you’re down in counts and not getting that mistake it really hurts you. I just try to go up there and battle as best I can and try to get on base for the guys behind me.”

Facing adversity

When Harper debuted in late April, he became the youngest major leaguer in seven years. The Nationals did not consider his place in the majors permanent. His presence alone, as an everyday outfielder batting second for a first-place team, is remarkable.