Dodgers Haven’t Gotten What They Hoped For From Roki Sasaki

A Tough Transition

Sasaki’s numbers through his first eight starts in MLB have left much to be desired for Dodgers fans.

Through his first 34.1 innings pitched, he owns a 4.72 ERA with just 24 strikeouts and a staggering 22 walks in that span. On a rate basis, he maintained a 15.6% strikeout percentage, 14.3% walk percentage, and 1.485 WHIP.

Worse yet, he has seen similarly poor results during his recent rehab starts in Triple-A. It is perfectly normal to expect some rust and lingering discomfort while returning from injury. However, Sasaki’s 6.75 ERA and 5.79 BB/9 over his 18.2 innings of rehab work is enough cause for concern.

These numbers are a far cry from his best year in NPB (2023), where he posted a 1.78 ERA with a 39.1% strikeout rate and 4.9% walk rate. For perspective, these rates together create a 34.2% K-BB rate. This year in MLB, that number has plummeted to just 1.3%.

Sasaki first hit the injured list in May with a right shoulder impingement, with many speculating it may end his season. He was likely already grappling with health concerns prior to his move to MLB as well.

This is demonstrated in the downward trends evident within his underlying pitch metrics from 2023 to 2024. 

For example, Sasaki averaged 98.9 MPH on his fastball in 2023 while managing some impressive vert. However, that figure dropped to 96.9 MPH in 2024, and has lost nearly another full tick in 2025 (96.0 MPH). 

He has seen even more dramatic falloff in the velocity of his breaking and offspeed pitches. Sasaki’s slider in particular fell from 87.5 MPH on average to just 82.0 MPH in 2025. His splitter similarly fell from 89.5 MPH to 84.8 MPH on average over the same span.

Further Signs of Decline

These drops in velocity have also been accompanied by significant issues with command and some degradation of his movement profiles. 

This had not been the case in Japan, where Sasaki generally maintained more effective command despite throwing harder. While he averaged 2.0 BB/9 over his four seasons in NPB, he has averaged 5.8 BB/9 with the Dodgers thus far.

Sasaki has been unable to command the strike zone overall, which has exacerbated his poor results. His splitter has remained effective, but he throws it in the zone just 29.6% of the time. This stands in stark contrast to his fastball, which he throws in-zone 64.2% of the time.

Batters can more reliably afford to take the splitter if they recognize it, so there is a greater burden on Sasaki’s fastball and slider. While his slider has mostly survived with a 33.3% whiff rate, his fastball has gotten crushed.

Hitters have whiffed just 10.1% of the time against the pitch, and have registered a 52.1% hard-hit rate against it. This is in good part due to diminished pitch characteristics from his time in NPB.

Sasaki maintained very high velocity with strong induced vertical break in Japan, leading to his fastball being a great pitch. However, this has not been the case in MLB. 

Injuries and mechanical inefficiencies, along with adjusting to the new ball and league environment, have greatly weakened Sasaki’s fastball. 

The pitch has averaged just 14.3 inches of iVB in 2025, which is 1.5 inches below MLB average. While the pitch has above average horizontal break, the deadzone nature of his fastball has made it an easy target at lower speeds.

Righting the Ship

It seems that Sasaki is unlikely to have a spot in the rotation for the remainder of this season. With the postseason on the horizon and Sasaki still having yet to make his return from the injured list, both his candidacy and capacity will be in question.

Things have been somewhat bleak at points during Sasaki’s first year in Los Angeles. However, there have recently been more encouraging signs for his immediate future in MLB.

Many of the aforementioned flaws that have cropped up during this season were absent during Sasaki’s most recent Triple-A start. Firstly, he averaged 98.3 MPH on his fastball, surpassing 100 MPH six times and topping out at 100.6 MPH.

His other offerings saw similar increases, with his splitter and slider sitting around 87.1 MPH and 90.7 MPH, respectively. While he began to slow down in the latter two innings of his start, it certainly lends to a more optimistic outlook.

Sasaki was tagged for three earned runs in the fifth inning, and walked four batters. However, he allowed no hits prior to this and struck out eight batters over his total 4.2 innings of work.

After the outing, Sasaki traveled to Los Angeles to meet with the Dodgers coaching staff. It was later reported that he had suffered a minor calf injury during the outing, and would make at least one more rehab start before returning to the big leagues.

No final decision has been made yet regarding Sasaki’s return to the Dodgers, but he certainly seems closer to coming back than he did a week prior.

The Future for Sasaki

If Sasaki does indeed return to MLB for a postseason run, it is unlikely to be as a starter. The Dodgers’ rotation is packed to the brim, with several others already vying for limited postseason spots.

However, Sasaki could potentially come back as a reliever for now. In fact, it may even be in his best interest. After Sasaki’s most recent rehab start, manager Dave Roberts was asked about the potential for Sasaki to rejoin the Dodgers in the bullpen. 

Roberts indicated that “anything’s possible,” and stated,  “I know he wants to contribute. So we’ve just got to see where he fits in. And we’ll have that conversation as an organization.” 

While far from confirmatory, Roberts left the door open for the possibility. He acknowledged that it would be a bit of a learning curve for Sasaki. However, given Sasaki’s situation, a bullpen role may be more ideal for the time being.

Sasaki has struggled with velocity all season, and is still in the process of returning from injury. That said, it may prove easier for him to empty the tank and pitch at max effort 1-3 innings at a time.

The risk for re-injury is always there, becoming increasingly more volatile at higher velocities. Not to mention, relief outings pose a bit of risk in high-leverage situations given Sasaki’s presumed unfamiliarity in the role.

However, the concerns around Sasaki’s health and performance indicate that this may be the Dodgers’ best option. Whether he returns in 2025 is still unclear. Even so, it will be very interesting to see how he adapts moving forward.