Mark Prior confident in seeing different Roki Sasaki after injury return

The beginning of Roki Sasaki's career with the Los Angeles Dodgers has not gone as expected for any of the parties involved.

Sasaki is just 23 years old, but wielding an unhittable splitter and a 2.10 ERA over four seasons as a pro in Japan, he's the best international pitching prospect we have seen in years.

He was advertised as the next great Japanese starting pitcher. He was supposed to follow in the footsteps of Yu Darvish and Masahiro Tanaka. Fair or not, the expectation was for Sasaki to look like a frontline starter as a rookie. Even older starters like Shōta Imanaga and Kodai Senga have been able to accomplish that in recent years.

Unfortunately, Sasaki got out to a rough start with a 4.72 ERA in his first eight outings with the Dodgers. He then landed on the Injured List with a shoulder impingement. Sasaki has not pitched since May 9.

Thankfully, Dodgers pitching coach Mark Prior is giving Dodger fans a reason to remain optimistic about Sasaki after he returns. Prior believes that the shoulder injury was actually the reason for Sasaki's struggles. When he comes back healthy, Prior expects to see the dominant pitcher that took Nippon Professional Baseball by storm.

“Clearly, he was bothered by it last year at times in Japan, and it’s kinda reared its head again a little bit,” Prior said. “I think you kinda have two different paths going on here. You have a development path overlaid with him trying to perform at the major league level, and those things aren’t easy."

"Clearly the velocity continued to trend down. And finally he got to the point where he spoke up and we’re glad he did, because I think it’s something we needed to address, his overall shoulder conditioning and strength," said Prior.

In Japan, Sasaki was touching 102 mph with his fastball on occasion, but consistently sat between 98-100 mph. That's not even close to what he has done for the Dodgers in 2025. Sasaki's average fastball in 2025 is 96.0 mph, but he was down near 94 mph before finally going on the IL.

Dodgers' Roki Sasaki could come back from injury looking renewed (as long as one thing returns)

Velocity is without question something Sasaki needs to be succesful. Mark Prior seems to have confidence that it will return to where it needs to be with some rest and conditioning.

But let's not forget that this shoulder injury is also something Sasaki was working through in Japan. There's a chance that this is a chronic injury he will battle for his entire career. It could be linked to his throwing potion or pitch mechanics.

What does MLB Roki Sasaki look like if he's regularly watching his fastball velocity dip to 94 mph? Can he still be productive?

I wouldn't say it's time to panic. The "development path" that Prior laid out could take some time. The Dodgers just need to remain patient with Sasaki and not push him too hard to take the mound.

But even then, I must admit that I have some doubts about if we'll ever see the version of Sasaki that dominated overseas in a Dodger uniform.