In the next 10 days or so, sidelined outfielder
"Andre's kind of taken that spot, to be honest with you," Mattingly said.
Crawford started the season as the team's starting left fielder, but has been sidelined since late April because of a torn side muscle.
Ethier has started the majority of games in left field in Crawford's absence.
Heading into the Dodgers' three-game series against the Chicago Cubs at Wrigley Field, Ethier was batting .275 with nine home runs and 27 runs batted in.
Ethier, 33, hit only four home runs last season.
Right-handed-hitting Scott Van Slyke will start in left field Monday night, with the Dodgers scheduled to face left-hander Tsuyoshi Wada.