Behind the smile was considerable pain, according to teammate Hanley Ramirez.
"He's pretty upset," Ramirez said. "He looked like he was going to cry. I know he loves this game so much."
Kemp said he would travel with his teammates during the playoffs.
"I'll be there cheerleading like I have been the whole year," he said. "I'll be the loudest one on the bench, waving a towel."
Kemp sounded confident the Dodgers would be fine without him.
"They've done pretty well without me," he said. "I think they're going to be OK. I feel like we have the best pitching going into all those games. I like our chances."
Ethier has been hitting in simulated games in Arizona, but still hasn't tested his left leg on the basepaths. He is scheduled to return to Los Angeles on Monday and work out with the Dodgers on Tuesday.
If Ethier is still in pain, he will be relegated to pinch-hitting or left off the 25-man playoff roster. That would force the Dodgers to start Schumaker in center field.
Schumaker batted .263 with two home runs and 30 RBIs in 125 games. He was the starting center fielder for the St. Louis Cardinals in Games 5, 6 and 7 of the 2011 World Series, which they won.
"This guy was a starting center fielder in Game 7 of a World Series before," catcher A.J. Ellis said. "He's not going to be overwhelmed by the situation. He's a world champion player. He's somebody we're all going to lean on for experience as we go on this run."