"I deeply regret it", said Gurriel.
Gurriel pulled at the corners of his eyes, which some interpreted as a slap at Darvish, who is of Japanese ancestry.
After the game, which the Astros won 5-3 to take a 2-1 lead in the best-of-seven series, Darvish called the gesture "disrespectful". After returning to the dugout, television cameras showed Gurriel making a slant-eyed gesture.
But neither the Astros nor the Major League Baseball Players Association are likely to go for that.
Darvish responded as well, taking to Twitter to ask everyone to focus on moving forward from the incident.
'I would particularly like to apologise to Yu Darvish, a pitcher that I admire and respect.
"I believe based on my conversation that he understood that both the language and the gesture were offensive", Manfred said.
The Astros' manager A.J. Hinch described Gurriel as "remorseful", according to the L.A. Times.
"Acting like that, you just disrespect all the people around the world", he said in Japanese through a translator.
Federer comes through Basel battle, Del Potro charge continues
Federer lost the opening set after a rusty display but battled back to win 4-6 6-1 6-3 in front of his home town crowd. Roger Federer has a lot of room for improvement after only just shading Adrian Mannarino in the Basel quarter-finals.
"No-one is ideal", Darvish posted on social media.
Darvish is not Chinese; he was born in Japan to a Japanese mother and Iranian father.
The MLB has recently suspended players caught using slurs.
'There is no excuse or explanation that makes that type of behavior acceptable, ' he said.
Fans praised the pitcher' response, but many were unimpressed with Gurriel's apology.
'I see a difference between behaviour from one player directed specifically at a player and a logo, ' he said.
Manfred also justified not banning Gurriel for the World Series because he wanted a loss of salary involved and because Gurriel, who could play while appealing any suspension under Major League Baseball's collective bargaining agreement with its players union, would not appeal this move.