(Pat Sullivan/AP)

In the Nationals’ 4-3 victory over the Astros on Wednesday, Harper extended his second-half skid by going 0 for 3 with two walks. He twice argued with home plate umpire Angel Hernandez after controversial calls. In the ninth inning, Harper made an ill-advised throw, trying in vain to throw out the tying run at third base while the winning run moved into scoring position. That convinced Johnson that Harper required a break.

“There were some questionable pitches, but he’s pressing a little bit,” Johnson said. “I think I’m going to give him a day off tomorrow. I thought that overthrow was a little frustration. We put him in some situations that he likes to be in, and he didn’t have good at-bats, so we’ll let him step back a little bit.”

Harper, at the urging of veteran teammate Jayson Werth, declined to comment to reporters who approached after the game. “No, sorry,” he said.

Harper’s squabbles with Hernandez served as a kind of undercard. In the second inning, Harper looked at a pitch from Galarraga that appeared to be both low and outside. Catcher Carlos Corporan’s mitt nearly scraped the dirt. Harper stepped back in the box to prepare for the next pitch as Hernandez rung him up with strike three. Harper barked and pointed at Hernandez, inches from his face, before first base coach Trent Jewett stepped in.

Hernandez told a pool reporter he did not consider ejecting Harper. “Let him have his say,” Hernandez said. “Nothing wrong with that.”

In the sixth inning, Harper came to the plate in a crucial spot. The Nationals had loaded the bases with no outs, and then watched as Gio Gonzalez grounded out for a force out at home and Steve Lombardozzi popped out in foul territory. With the Nationals leading by a run, the inning fell to Harper.

Harper got ahead in the count, 3-1, and then took a pitch low and outside from reliever Xavier Cedeno. He dropped his bat and started jogging to first as Hernandez called a strike. Harper took a few more steps before he decided to believe Hernandez had really made the count full.

Cedeno fired another pitch low and away, closer to the strike zone than strike two. Harper watched it, and Hernandez called him out looking for the second time. Harper cocked his bat with one hand, as if he was going to throw it, then restrained himself. He chucked his helmet and tossed his bat, and as he ripped his batting gloves off in the middle of the diamond he shook his head.

“I talked to Angel about it right after that at-bat,” first baseman Adam LaRoche said. “I said, ‘What’s going on? From where I’m at, those balls are down.’ He assured me that they were good pitches. He said he would never do that to Bryce, he loves him, he loves the way he plays and that there’s no kind of initiation there. He called it the way he would call it to anybody.”

LaRoche said he hoped umpires would be more professional than to single out a 19-year-old rookie, but he admitted the subject had come up.

“I’ve been in that position,” LaRoche said. “I’ve talked to Bryce a lot about it. I said, ‘You’ve got to keep your mouth shut, but at some point, if it gets really bad you’ve got to stand up for yourself and not sit there and take it.’ Especially as competitive as he is, he’s done it right for the most part. He’s held his tongue and, eventually, you lose it and he’s going to let somebody know about it. Again, I haven’t gone back and seen ’em, so I don’t know if they were close or how bad they were. Angel told me they were good pitches.”

Since the all-star break, Harper is hitting .176 with two homers, 26 strikeouts and 15 walks in 116 plate appearances. Johnson has repeated Harper does not need a physical rest. But now, he thinks he needs a mental break.