Los Angeles Dodgers first baseman Joc Pederson was substituted in the eighth inning of Monday's 9-1 loss to the Colorado Rockies because he didn't run out a ground ball, manager Dave Roberts said.

Pederson grounded out in the eighth to first baseman Daniel Murphy, scoring catcher Will Smith. But Pederson, who went 0-for-4 in the game, didn't reach first base and stopped running.

Tyler White replaced him at first in the bottom of the inning.

"There's a certain way to play the game and I didn't see the effort there," Roberts told reporters.

Added Pederson: "Yeah, it was unprofessional. I let the emotions get the best of me. ... I'm better than that."