Yoshinobu Yamamoto injury update: Dodgers' $325 million ace to begin rehab assignment after two-month absence

Los Angeles Dodgers right-hander Yoshinobu Yamamoto will take the next step on Wednesday toward returning from the triceps injury that has sidelined him since mid-June. Yamamoto is expected to make a brief rehab start for Triple-A Oklahoma City, the first of at least two before he slots back into the Dodgers' rotation, according to MLB.com .

Yamamoto, 26, has not pitched since June 15 after experiencing tightness in his triceps during a start against the Kansas City Royals . Back then, Yamamoto explained that he had first felt the tightness while warming up, but that he didn't feel it was notable.

"I did have tightness and I was aware of it [during the bullpen session], but it wasn't serious at that point. As I was pitching, it started growing," he told reporters at the time . "I let [the] coaches know, and we decided to pull me."

Prior to the injury, Yamamoto was showing why the Dodgers were willing to sign him to a 12-year pact worth $325 million before he ever threw a pitch in a Major League Baseball game. ( CBS Sports had detailed over the winter why he was considered to be the best pitcher in the world to have not yet done so .) In 14 starts, Yamamoto had compiled a 2.92 ERA (137 ERA+) and a 4.94 strikeout-to-walk ratio.

The Dodgers' rotation has been hit hard by injuries all season. Even now, they remain without ace Tyler Glasnow , Tony Gonsolin , Dustin May , Emmet Sheehan , and River Ryan , as well as top prospect Nick Frasso . Still, the Dodgers have seen Clayton Kershaw and Walker Buehler return from injury over the course of the summer, albeit to varying levels of success.

The Dodgers enter Wednesday with a 78-54 record on the year, giving them a three-game edge in the National League West over the Arizona Diamondbacks and San Diego Padres .