The Dodgers optioned Barnes to Triple-A Oklahoma City on Tuesday.
Barnes was brought up to the big club Monday, but he'll now be pushed off the active roster without making an appearance for the Dodgers to make room for Blake Snell (elbow), who returned from the IL to start Tuesday's game against Kansas City. Barnes has given up 10 runs in 13 major-league innings this season but could return to Los Angeles down the stretch to provide a fresh bullpen arm.