"I know he's remorseful," Astros manager A.J. Hinch said.
After hitting a home run in the second inning off Darvish, Gurriel returned to the dugout, where he put his fingers to the side of his eyes and appeared to say a derogatory Spanish term.
Even Darvish -- born in Japan to a Japanese mother and Iranian father -- tweeted, "No one is perfect. What he had done today isn't right, but I believe we should put out effort into learning rather than to accuse him ... Since we are living in such a wonderful world, let's stay positive and move forward instead of focusing on anger."
Gurriel continued, "In the moment, I didn't want to offend him or nobody in Japan because I have a lot of respect for them and I played in Japan," he said, adding that, "I didn't mean to do it."
Gurriel played in Japan in 2014 before signing with the Astros last season.
Dodgers outfielder Enrique Hernandez described the situation as "disappointing."
"It's just unfortunate that he did that right after the homer and not thinking the cameras were on him," Hernandez told reporters. "I'll let the league handle [potential discipline]. I'm not the right guy to handle that one."