Roki Sasaki’s Revamped Splitter Jumps Nearly 6 MPH in Velocity

Here’s an in-depth look at how Roki Sasaki has sharpened his most dangerous weapon—and what it might mean for his MLB trajectory. The focus is on Sasaki’s midseason adjustments, how his splitter took center stage in the Dodgers’ 12-4 win over the Cubs, and what coaches and teammates are seeing as he learns to mix velocity, spin, and decision-making to keep hitters guessing.

Splitter retooled: Sasaki’s midseason adjustment pays off

After a rookie season that showed flashes of promise but suffered from inconsistent fastball sequencing, Sasaki decided to lean into a retooled splitter. The Dodgers let him trust the pitch deeper into games, and even though he gave up four runs and three solo homers, the approach had its moments.

Pitch profile and in-game results

The numbers paint a pretty clear picture. Sasaki threw his splitter 48 times—one of the highest rates he’s posted in a big-league start.

The pitch averaged 90.8 mph, which is about 5.8 mph faster than his season average. The splitter’s spin rate spiked to 991 rpm, way up from his usual 574 rpm.

This profile looks a lot like the splitter he used during the 2023 World Baseball Classic. Back then, it hovered around 91 mph with about 1,100 rpm of spin.

Dodgers manager Dave Roberts said the pitch tunneled better with the fastball, staying in the zone a bit longer and forcing hitters to make earlier decisions. That’s a subtle but important tweak.

The harder splitter got him a career-high nine whiffs and landed as a first-pitch strike in nine of ten at-bats. That’s the kind of thing that can put hitters on their heels from the jump.

Catcher Dalton Rushing pointed out how the splitter’s early-zone location made hitters chase later in counts. That’s a good sign for depth and deception.

• Split-finger usage: 48 pitches in the game
• Average velocity: 90.8 mph
• Spin rate: 991 rpm
• Season-spin baseline: 574 rpm
• First-pitch strikes: 9 of 10
• Whiffs in the outing: 9
• Outing length: Reached the sixth inning for the first time this year

Manager and catcher perspectives

Roberts emphasized how much it means to see Sasaki willing to adapt. That kind of midseason evolution is what separates pitchers who just survive from those who really thrive.

The Dodgers’ plan to let Sasaki use the splitter as a primary weapon against righties shows real confidence in his growth. It’s also a pretty smart way to attack opposing lineups as the season wears on.

Dalton Rushing added that the splitter’s early strikes forced hitters to open up their decision window, giving Sasaki more room to play with later in counts. When a catcher and pitcher are that in-sync, it usually means more swings and misses, and fewer easy walks—exactly what happened in this outing.

Takeaways: Sasaki’s growth plan and what it could mean for his future

• Trust in growth: The midseason pivot shows a pitcher willing to change mechanics and sequencing to get better results.
• Weaponization of the splitter: A heavier, more deceptive splitter could help Sasaki go deeper into games and rack up more whiffs.
• Momentum for the Dodgers: Success with the splitter might let Sasaki rely less on pure velocity, giving him a steadier, more sustainable approach.

What this means for the Dodgers and MLB

For the Dodgers, Sasaki’s evolution lays out a real blueprint for turning raw talent into a reliable mid-rotation arm. That improved splitter—quicker, tougher to track, and trickier for hitters to read—brings a new challenge for even the most experienced lineups.

MLB watchers see Sasaki’s willingness to change things up on the fly as a sign of something bigger. Here’s a young pitcher who doesn’t just rely on his natural gifts; he’s building a smarter, more adaptable style that mixes speed, movement, and clever pitch sequencing.

 
Here is the source article for this story: Sasaki shows off retooled splitter — with velo up nearly 6 mph