(AP Photo/Alex Brandon)

Nationals Manager Matt Williams yanked Bryce Harper from the Nationals’ 4-3 loss to the Cardinals Saturday afternoon for “lack of hustle” and “the inability to run 90 feet” after Harper failed to reach first base on a groundball back to the pitcher in the sixth inning, a decision the rookie manager stood behind even after Harper’s spot in the lineup came up during a ninth-inning rally that fell one run short.

“We made an agreement,” Williams said. “He and I made an agreement. This team made an agreement that when we play the game, that we hustle at all times, that we play the game with intensity and the willingness to win. As it turned out, his spot came up. Kevin Frandsen put on a nice at-bat against [Trevor] Rosenthal. But his spot came up with the ability to win the game. That’s a shame for his teammates.”

Harper said he “absolutely” understand Williams’s decision and “I respect what he did. It’s part of the game.”

“I unequivocally support the manager’s decision 100 percent,” General Manager Mike Rizzo said.

Harper had been dealing with tightness in his quad, which sidelined him Wednesday night in Miami. Harper said he’s “fine” physically and the injury did not prevent him from running to first base. Williams said the incident will be forgotten, and Harper will return to the lineup Sunday.

“It’s the way we set out to do it,” Williams said. “Regardless of situation, regardless of what’s happening to you personally, we have to play the game a certain way to give ourselves the best chance to win. And it’s too bad that it came down to that situation in the ninth inning, when he could have been at the plate. For the sake of his teammates, and the sake of the organization, he needs to play with aggression and the way he plays.”

Leading off the sixth inning, Harper tapped a fastball back to Cardinals pitcher Lance Lynn, who snared it on a chest-high hop. Harper jogged out of the batter’s box and peeled off halfway to first base. Once he returned to the dugout, Harper said, Williams informed him, “Kevin’s going to left.”

Williams cited the new, stricter enforcement of the transfer rule as one reason why Harper’s jogging upset him so much.

“He’s an exciting player,” Williams said. “People come to pay money and watch him play, and watch him play the way he can play. And it’s pretty exciting. It’s pretty dynamic. But there’s another side to it. The other side is, regardless of how the ball comes off the bat or regardless of how he’s feeling about an at-bat, he must maintain that intensity and that aggressiveness. And that means running all the way to first base and touching the base.

“There’s a million reasons why. The transfer rules that we’ve seen lately. What if that guy bobbles the ball as he’s throwing it around? If he doesn’t touch the base, he’s out. If he’s in the dugout, he’s automatically out. Beyond the all the just-run-90-feet stuff, there’s a real, tangible rule behind it now. So we must do that. And he understands that.”

In the ninth inning, the Nationals rallied against Cardinals closer Trevor Rosenthal. With one out and runners on second and third, with Washington trailing by two, Harper’s spot in the order came up. Frandsen plated one run with a sharp grounder to third, but Jayson Werth ended the game with a strikeout.

“Man, it’s tough to watch,” Harper said. “Being able to be up there in that situation is something that I thrive on and I want to be in. It’s in the past, nothing we can do about it now.”

Teammates mostly steered clear of evaluating Williams’s decision.

“It has nothing to do with me,” Werth said. “I’ve played on teams where if you don’t hustle, you get taken out of games. Pretty standard. You talk about taking care of your area — that’s not my area. I think it’s part of the game. You show up here. You be on time. You hustle. Not a lot is asked of us. But we’re focusing on one, small part of the game, I feel like.”

“That’s up to Matt,” starter Jordan Zimmermann said. “I don’t have much to say about that. I try to stay out it. Hopefully he learns, I guess.”

“Coach’s decision,” Danny Espinosa said.