Roki Sasaki is too predictable, Jorge Polanco is keeping it simple and more

New York Times

20-05-2025

Roki Sasaki started this year with high expectations for his MLB debut season. However, his ERA sits at 4.72 through his first eight starts, and deeper signs of struggle are beneath the surface. Meanwhile, Jorge Polanco — mainly limited to left-handed hitting due to injury — is quietly having the best season of his career in Seattle. Today, I will dive into what is causing Sasaki's struggles and whether Polanco's performance is sustainable.
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While moving from Japan comes with challenges and adjustments, let's dive into what is causing Sasaki's struggles on the mound with the Dodgers and whether he can improve.
There are four issues I'm seeing for Sasaki:
In Japan, Sasaki's fastball averaged 98-99 mph, reaching 101 mph at times in 2023. Based on international scouting reports, his average fastball velocity in 2024 was closer to 97 mph.
This season, he started hot, hitting 100 mph in his first start. However, his velocity has been steadily dropping since, leading to a season average velocity of 96 mph.
Sasaki's 14% walk rate is in the bottom 4% of MLB. His below-average first-pitch strike rate is a contributing factor, as he consistently falls behind in counts. This is leading to problems getting outs, and I will discuss this more when I get to his attack vs. righties.
He throws three pitches: a 96 mph four-seamer, an 85 mph splitter and an 82 mph slider. However, the slider is not an effective pitch, as Sasaki can't control it. He mainly throws it against righties, but it consistently does not fool hitters and results in balls. Its two-strike conversion rate (percent of pitches resulting in a strikeout) is the ninth-worst in baseball among pitchers who have thrown at least 100 sliders.
Looking at the pitch chart, it is clear why. Many of these sliders are not thrown in competitive locations. They rarely get chased low and don't induce swings when thrown inside. Even some of the strikes called on the inside are borderline pitches. This is his only breaking pitch, and Sasaki can't land it for strikes consistently.
Overall, hitters are not chasing his stuff. All three of his pitches result in well below-average chase.
As a result, he needs to throw more in-zone.
This is the biggest problem I see with Sasaki — his pitches are not finishing off hitters. We already saw that none of his pitches are getting chased, meaning he needs to throw in-zone. But his two most relied on pitches are also not getting missed when thrown in-zone:
If they are not getting whiffs, then ideally they would be getting ground balls or weak contact.
Of his three pitches, only the four-seamer is getting more ground balls than average, which is interesting because the four-seamer is not typically a ground ball pitch. In terms of contact, only the slider has a hard hit rate that is better than average. The four-seamer and the splitter are consistently resulting in hard contact:
So he is not getting chase, whiffs, ground balls or soft contact, making it much harder for him to get outs.
As a right-handed pitcher, Sasaki should be doing better than he is against righties. So far this season, he has a 4.82 FIP.
In addition to the issues discussed previously, Sasaki is also very predictable against righties.
Looking at his pitch usage, he leans heavily on his four-seamer. The only situation where he mixes his pitches is with two strikes. The four-seamer usage is so high when he falls behind (which occurs more often than average) that, in full counts, hitters can expect a fastball. Even the first pitch four-seamer usage is high enough for hitters to anticipate attacking early.
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On Tuesday, May 13, the Dodgers placed Sasaki on the 15-day injured list due to right shoulder impingement. While this injury may have affected his results a bit, Sasaki's lower velocity, below-average control, poor pitch results and predictable game plan have made it hard for him to see consistent success at the MLB level so far. If Sasaki is to see better results upon his return, he will need to do a better job throwing competitive pitches, getting ahead in counts and fooling hitters.
Despite not being 100% healthy, Polanco is off to a hot start this season with a 1.021 OPS through 34 games. A switch hitter his entire career, Polanco started this season batting as a lefty for the majority of the time due to dealing with soreness when batting from the right side — just 12 plate appearances as a righty. In his career, Polanco has been more successful as a left-handed hitter:
In 2025, his stat line as a lefty is even more impressive: 113 PAs, 12% strikeout rate, 6% walk rate, 1.026 OPS.
The two biggest differences are his contact quality and bat-to-ball ability on the left side. His average exit velocity is a career-high 92.2 mph, and his .614 xSLG ranks eighth in MLB.
He is also doing significantly better in the heart of the zone.
In terms of his bat-to-ball ability, he's cut his strikeout rate significantly compared to his career numbers when batting left-handed and is making more contact in-zone while missing less overall.
Looking at his mechanics, it looks like Polanco has simplified his pre-pitch stance and load this season:
Starting with pre-pitch, Polanco is standing more closed and is straighter in the box. His hands are also elevated compared to the end of 2024.
Looking at his load position, there are several key differences. In 2024, Polanco loaded with a dramatic leg raise that shifted his weight completely to his back leg before pausing and swinging. In 2025, we are seeing a much more subtle leg raise with a more fluid shift in weight that transfers his power more effectively to his swing. Overall, it is quieter and more athletic. As a result, he is barreling and translating his power into games effectively this season.
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While his strikeout rate is lower and his contact quality is improved, his plate discipline is similar to that of his career. The biggest change is that he is ambushing the first pitch a career-high 35% of the time. He's only seeing first-pitch fastballs 45% of the time, so he's not just targeting fastballs. He is more prepared to attack any first pitch he likes in-zone.
Overall, Polanco's start in 2025 is not just luck; it is due to adjustments and the situation. Hitting lefty and simplifying his swing have allowed him to improve his contact while maintaining power.
Even though the Dodgers are losing Roki Sasaki for a short time, they have no shortage of pitchers ready to step up. With Tony Gonsolin back and Clayton Kershaw's activation off the IL, the rotation remains strong. While it is great to have depth, this talent also blocks younger players from having an opportunity to start long-term. RHP Ben Casparius, for example, is someone I see as a rotation piece on most other teams around MLB. He is expected to be a long reliever for the Dodgers, but if he's traded, he can certainly take on a higher role as a starter with a new team. He has strikeout stuff, the ability to face both hands, and above-average control. His development and progress, though potentially overshadowed in Los Angeles, are worth keeping an eye on.
Ozzie Albies is having a rocky start to the season with a .616 OPS. His struggles stem from a decline in contact quality, particularly power. This season, he is not hitting the ball as hard as in past years. His maximum exit velocity is 107.2mph (down about six mph from last season), and his hard hit rate ranks 10th-worst in baseball at 26%. This may partially be due to him seeing fewer fastballs than in years past, but his power against fastballs has also declined. This trend is seen for Albies as both a lefty and righty, but is significantly worse as a righty hitter. Albies has historically done very well from the right side, so this is particularly concerning. Something to keep an eye on for improvement would be if he starts making hard contact consistently again soon, at least from one side of the plate. It's hard to say he'll be back to normal without seeing his exit velocities rebound first.
The Rays' Brandon Lowe is also having a worse-than-anticipated start to the season, stemming from increased misses in the zone. He has a .416 OPS against lefties this season, and the Rays recently benched him against Max Fried. This was particularly telling as the Rays' lineup has been underwhelming overall. Lowe's struggles are not related to his contact quality, which remains strong, but rather, he is missing too many pitches in-zone, especially fastballs. If he is going to bounce back this season, the improvement will begin when he starts making more contact in-zone, especially against hard pitches.
(Top photo of Roki Sasaki: Christian Petersen / Getty Images)