Ramirez, struck by a Joe Kelly fastball in the first inning of Friday's 13-inning loss, was scratched from the lineup less than an hour before game time with bruised ribs.
"Hanley's sore today," said manager Don Mattingly. "He got it pretty good."
Ramirez underwent X-rays, which came back negative.
According to Ramirez, he will undergo a CT scan Sunday. He said he would do everything he could to get back on the field for Game 3 Monday in Los Angeles. The Dodgers are down 0-2 in the series.
"This is our time and you cannot shut down even if you have little things," Ramirez said.
Ramirez batted .345 in the regular season and is hitting .444 with a home run and six RBIs in the playoffs thus far. He was replaced in the lineup by Nick Punto.
Ethier was held out of the lineup a day after making his first start in center field in more than four weeks.
Ethier moved slowly around the bases Friday and missed a Carlos Beltran line drive that went for a two-run double in the Cardinals' 3-2 win in 13 innings in Game 1. Ethier said after the game he felt like he should have caught it.
Shortly after the game, Ethier entered the Dodgers clubhouse accompanied by the Dodgers' team physician, so he may have undergone further examination after the game.
Ethier was replaced in center field by utility man Skip Schumaker, who played the entire NLDS in center field, batting .231.