Inside Roki Sasaki's tweaked repertoire as disappointing Dodgers rookie tries to earn a playoff role
Sasaki, who has not pitched in the majors since May, is still trying to get back on track to end his first MLB season
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3 min read
The Los Angeles Dodgers can punch their ticket to the postseason as soon as Friday night. Once they secure a place in the tournament, they can turn their attention to other matters, be it securing yet another NL West crown or figuring out if there's a role on the playoff roster for right-hander Roki Sasaki.
Sasaki, 23, was one of the most hyped free-agent signings of last winter. He's been sidelined since early May with a shoulder impingement, but he's continued to work his way back toward the active roster with a series of rehab appearances. Prior to the injury, Sasaki had not lived up to the lofty expectations placed upon him following his storied career in Japan. Instead he posted a 4.72 ERA (89 ERA+) and a 1.09 strikeout-to-walk ratio while averaging under five innings per pop.
At first blush, Sasaki's return to the mound would seem to be little more than a resumption of his old ways. He's tallied a 6.75 ERA and a 1.33 strikeout-to-walk ratio in five appearances to date, with at least one more to come. Yet a closer look at Sasaki's ball-tracking data indicates that he's made a number of sensible tweaks to his arsenal.
The main difference between this Sasaki and that Sasaki has to do with his breaking ball usage. When he last appeared in the majors, he was operating with a three-pitch mix: four-seamer, splitter, slider. He's since mothballed his sweeping slider, installing in its place a cutter that features close to 10 fewer inches of cut. Here's a look at how those two pitches have fared, albeit in small samples. (Do note that the cutter has so far only been used in the minors.)
| Pitch type | No. thrown | Whiff% | Zone% | Chase% |
|---|---|---|---|---|
Slider | 101 | 33.3% | 38.6% | 14.5% |
Cutter | 21 | 50% | 52.4% | 20% |
Again, that's a laughably small number of cutters to be drawing big conclusions from. You can understand the theory behind the trade, however. Sasaki wasn't having success throwing his slider either within the zone or in locations outside of the zone that elicited chases. He appears to have better command over the cutter, showing some feel for locating it on both sides of the plate. Should that hold up, the cutter would serve as a complimentary pitch to his fastball, giving him another pitch he can steal strikes with while providing hitters with a different look.
Another tweak worth watching has to do with the possibility that Sasaki has added a sinker to his toolbox. He's only thrown three so far, according to pitch classification algorithms, and none of them have landed in the zone. Still, this is another of those developments where the thinking is easy enough to grasp. As I noted on several occasions over the winter and early in the spring, Sasaki's four-seam fastball features dead-zone properties -- in short, it moves as much horizontally as it does vertically, making it easier for batters to track.
There are a few tried and true ways for pitchers with dead-zone fastballs to combat those effects. One is having extreme velocity -- something that Sasaki's boosters noted was a point in his favor coming into the year. Another is to embrace a sinker, especially against same-handed batters. Keep in mind that Pittsburgh Pirates ace Paul Skenes also drew criticism for his four-seamer's shape, but he overcame those concerns in part by adding a sinker-splitter hybrid to his mix.
It's worth waiting to see if Sasaki is actually installing a sinker, or if he was just toying around. The Dodgers are as good at player development as any organization in the sport, so I have to imagine that further arsenal refinements will be on his winter to-do list, if nothing else. Something that might be on Sasaki's more immediate to-do list? Familiarizing himself with pitching out of the bullpen. That seems like Sasaki's likeliest role for the remainder of the season, provided, anyway, that he's up for the challenge.
"I think that Roki is … from my understanding, in a good place to do whatever it is to help the team," manager Dave Roberts recently told reporters. "[Pitching in relief] would be something that would be completely odd to him, so it would have to be a little bit of a leap of faith on his part, as well. But I think that he understands how good the starting pitchers are pitching. He just wants to be a part of it. He's worked really hard to get himself into a position to contribute."
With just more than a week remaining in the regular season, it's to be seen if Sasaki can make enough of an impression on the Dodgers to earn a spot on their playoff roster. At minimum, it's clear that he's putting in the work to make a bigger impact in due time -- be it this fall or next spring.
