A month later that battle has become a rout.
After going three for three with a home run in Wednesday's 7-5 loss to the Chicago Cubs, Pederson is hitting .429 with a .467 on-base percentage and a .750 slugging percentage and playing spectacular defense. Ethier is at .192/.231/.250 after a one-for-four day that included a double — his first extra-base hit of the spring — and his team-leading eighth strikeout.
But neither the Dodgers nor Pederson are prepared to call the battle won just yet.
"We're still in camp and we're still competing," Manager Don Mattingly said. "But obviously we like what we've seen from Joc. We're looking at Joc's processes as much as we are just the results. How's his work? Has he got good routines? How's he kind of dealing with it all?
"We haven't made any decision on who's going to be where. But we do like the way things are going for Joc."
Pederson was even more evasive.
"I just show up every day, go about the process that was set by the coaching staff," he said. "[I] work hard and try to do everything I can on the field to help the team win."
If you're looking for more than tired cliches from Pederson, you're probably going to be disappointed. The son of a former major leaguer, Pederson is well-schooled in the art of giving a cooperative — but not revealing — interview.
Pederson, 22, is breaking with family tradition in another way, though. While father Stu played 12 years in the minors, his big league career lasted just eight games with the Dodgers in 1985. And older brother Tyger didn't get that far, moving to the independent Frontier League after one season of rookie ball with the Dodgers.
But given his torrid spring, Joc, who played 18 games with the Dodgers last season, is determined to spend the rest of his career in the majors.
"Once you're up there, you never want to leave," he said. "You'll do anything you can to stay up there."
He's sparing no effort in trying to make that happen, having played winter ball for a fourth straight year. When he returned from the Dominican Republic, Pederson showed up at Dodger Stadium six days a week to take batting practice with hitting instructor Mark McGwire and minor league coach Johnny Washington. He was also an early arrival in Camelback Ranch, where he did daily drills to improve his defense.
"There's something to be said for having some time off," Mattingly said. "But the fact that he's come in here [and] looks good is the most important thing."
Pederson struggled in a brief trial with the Dodgers last September, collecting four singles in 28 at-bats. But he also walked nine times and played solid defense, allowing the team to feel comfortable trading Matt Kemp to San Diego.
The question now is whether Pederson has made the team comfortable enough to deal Ethier, who, like Pederson, is a left-handed hitter. The Dodgers' outfield appears set in the corners, with Carl Crawford in left and Yasiel Puig in right. And Ethier, who has played more games in center field the past two seasons (142) than any other Dodger, has already said he'd prefer to be traded if he's not going to play regularly.
Which is one reason why Mattingly refuses to name a starter, tepidly praising Either as well.
"Andre's at-bats have been pretty good," the manager said.
However, Pederson is clearly winning the battle — though he continues to look over his shoulder just the same. Which may be something else his father taught him.
"You can't take it for granted," Pederson said. "Because there's always someone coming for your job."
Just ask Andre Ethier.