WASHINGTON -- Manager Matt Williams made it known that he wasn't going to tolerate lack of hustle from anyone on the Nationals. He showed that he meant business on Saturday afternoon during the team's 4-3 loss to the Cardinals by removing Bryce Harper from the game.

Williams sat Harper down after the sixth inning. Harper led off the inning and hit a ground ball to Cardinals right-hander Lance Lynn. Harper didn't run all out to first base and was thrown out easily. After the inning ended, Harper was replaced by Kevin Frandsen.

"It was the inability to run 90 feet -- lack of hustle," Williams said. "He had to come out of the game. We made an agreement, his teammates made an agreement: When we play the game ... we hustle at all times. We play the game with intensity, with willingness to win.

"Regardless of the situation, regardless of what's happening to you personally, we have to play the game a certain way to give us the best chance to win. ... For the sake of the organization, he needs to play with aggression in the way he plays."

What made it worse was that Harper's spot came up in the ninth inning with Cardinals closer Trevor Rosenthal on the mound. The Nationals had runners on second and third with one out, when Frandsen grounded out to third baseman Matt Carpenter to plate Zach Walters and make it a one-run game. After that, Jayson Werth struck out to end the game.

Williams declined to describe Harper's reaction to being taken out of the game. Harper said he understood why Williams removed him, and it was tough for him to watch Frandsen take his at-bat.

"[Harper's] spot came up with the ability to win the game," Williams said. "That's a shame for his teammates."

Williams pointed out that Harper is an exciting player and that fans pay their money to see him play. But with rules in place on the field, Harper should know to hustle all the time, according to Williams.

"Regardless how the ball comes off the bat, regardless of how he is feeling about an at-bat, he must maintain that intensity and aggressiveness," Williams said. "That means running all the way to first base and touching the base. There are a million reasons why. The transfer rules that we've seen lately, what if that guy bobbles the ball as he is throwing it around and he doesn't touch the base, he is out. He veers to the dugout, he is automatically out. There is a real, tangible rule now, so we must do that -- and he understands it."

Harper has a reputation for respecting the game. He knows baseball history when it comes to Mickey Mantle and Jackie Robinson, for example. When asked if he felt bad about the situation that occurred on Saturday, Harper said, "No, ... it's how it is."

Harper has been dealing with left quad tightness, but he said he felt fine. Williams said he will not hold a grudge against Harper, who will be in the starting lineup on Sunday afternoon against the Cardinals.

Teammate Jayson Werth didn't seem surprised that Harper was taken out of the game.

"I've played on teams where, if you don't hustle, you get taken out of the game. It's pretty standard," Werth said. "You talk about taking care of your area, that's not my area."