Ethier hasn't started a game since Sept. 13 because of an ankle injury.
"It gets us back to the lineup we played for most of the year," Dodgers manager Don Mattingly said. "We're comfortable enough. He really had to tell us he was comfortable he could make all of the plays. He had to have confidence in that."
Mattingly and the Dodger front office weren't impressed with how Ethier was moving around during a Wednesday workout in Los Angeles, but Ethier did much better in Thursday's workout at Busch Stadium.
"A lot of the things I saw [Thursday] I really liked," Mattingly said. "As the day went on, he just got better and better."
Even with that, Mattingly said there's no guarantee that Ethier will be able to start Game 2, which will be Saturday afternoon.
Ethier became the Dodgers' regular center fielder in June, when Matt Kemp was hurt. His ability to handle the position enabled the Dodgers to play Ethier, Yasiel Puig and Carl Crawford in the same lineup.
Ethier batted seventh on Friday.
The entire Dodger lineup:
Carl Crawford lf
Mark Ellis 2b
Yasiel Puig rf
Juan Uribe 3b
Andre Ethier cf