Ethier hit in the second spot while Victorino batted sixth.
With the Dodgers facing a righty in Lance Lynn on Thursday, Mattingly said he made the move based on the matchup and thinks he will switch them back when they face their next lefty, which will be Saturday against Jaime Garcia.
Ethier, who is 0-for-8 batting second this year, is hitting .330 against righties compared with .223 against lefties. Victorino, a switch-hitter, is batting .306 against lefties compared with .238 against righties.
On Wednesday, Mattingly flip-flopped Matt Kemp and Adrian Gonzalez in the batting order, moving Kemp up to third and Gonzalez into the cleanup spot. They stayed in those spots for Thursday's game.