Andre Ethier completed his 2-game rehab assignment with the Quakes on Thursday, going 0 for 2 with a walk, a double play and an RBI groundout.

He was fine, said he felt good and was ready to return to the Dodgers from the strained oblique muscle.

But the Quakes may have suffered another injury. Starting catcher Chris O’Brien pulled his hamstring while running the bases in the third inning. Backup catcher Steve Domecus came in and doubled and scored later in the game in the Quakes’ 5-4 loss to the 66ers before 4,828 at the Epicenter.

The Quakes will need to get another catcher as manager Juan Bustabad said they would most likely place O’Brien on the disabled list. Domecus is the only other catcher on the active roster. Selme Angulo, who joined the team as a bullpen catcher, has not been activated since joining the team. Bustabad wasn’t sure if Angulo would be activated or if the Quakes would get someone else.

Meanwhile, the Sixers let a 4-0 lead slip away as the Quakes tied the score with one in the sixth, one in the seventh and two in the eighth.

“We had a great chance to take the lead,” Bustabad said. “(Jonathan) Garcia hit that one hard at the right fielder. If that drops in, we take the lead.”

In the ninth, the Sixers took the lead when Drew Heid led off with a single against Eric Eadington (1-1), was sacrificed to second by Taylor Lindsey, took third on a single by Kaleb Cowart, then scored on C.J. Cron’s sacrifice fly to center. It was Cron’s league-leading 74th RBI.

Daniel Tillman (1-1) pitched very well for the Sixers in getting the win. He entered the game with the score already tied and a runner on first and no outs in the bottom of the eighth. He retired three straight batters.

In the ninth, Domecus led off and was hit by a pitch. Scott Wingo sacrificed him to second and Casio Grider’s ground out sent Domecus to third. Tillman then struck out Leon Landry to end the game.