Don Mattingly: Julio Urias is in the September conversation.

CINCINNATI — The Dodgers’ front office is currently discussing potential call-ups in September, when rosters expand to 40. Mattingly has characterized the reinforcements as coming in two separate “waves,” one early in the month and another later on.

Asked about 19-year-old pitcher Julio Urias, Mattingly said his name has been discussed.

“He’s probably not one of the guys we would see right away,” the manager said. “We’ve talked about two waves of guys. He’s not one of the first waves of guys.”

Urias has struck out 71 batters in 62 ⅓ innings for Double-A Tulsa. He was limited to throwing 87 ⅔ innings at Single-A last year, and is expected to have a higher limit this year.

Even if Urias is called up, he might not pitch.

“You want to bring guys up for a purpose,” Mattingly said. “Sometimes it may just be for him to be here, and to experience being on the club and traveling and seeing other teams play.”

Carlos Frias exits Triple-A start after one inning.

PHILADELPHIA — Pitcher Carlos Frias experienced a back issue during his latest start for Triple-A Oklahoma City on Wednesday night and was removed after one inning as a precaution.

Frias was making his third start for the Dodgers’ top affiliate since he was placed on the 15-day disabled list July 1.

Curiously, the Dodgers did not announce that Frias had been activated from the 15-day disabled list and optioned to Oklahoma City at the time it happened. According to the transactions page on the team’s website, Frias was optioned Sunday.

So, the right-hander had been medically cleared to rejoin the Dodgers when he took the mound Wednesday night. That makes the latest setback at least somewhat more surprising.

Mike Bolsinger was removed from his start for Oklahoma City on Tuesday because he was struck on the forearm by a line drive. He’s expected to make his next start. Frias and Bolsinger are currently the team’s sixth and seventh starters.

Chin-Hui Tsao accepts outright assignment to Triple-A, earns save.

Pitcher Chin-hui Tsao, who was designated for assignment Thursday, accepted an outright assignment to Triple-A Oklahoma City and earned the save in the Dodgers’ win Saturday night.

Tsao recorded the final four outs in the game, his first since allowing six runs in two-thirds of an inning against the Mets on July 25.

The Dodgers designated Tsao, pitcher Brandon Beachy and outfielder Chris Heisey to accommodate the influx of a three-team, 13-player trade Thursday.