Masahiro Tanaka’s Splitter is the Key to His 2020 Success

The split looked pretty good in March.

Masahiro Tanaka will take the mound tonight for his season debut against Boston. Of course, the start comes just one month after Giancarlo Stanton drilled him in the face with a 112 miles-per-hour screamer in camp. This will be Tanaka’s first start in his first contract year since coming to America, so he’ll want to make all of his limited innings count in 2020. Whether or not he’ll be back in pinstripes next year may very well depend on how well he is able to utilize his splitter. It is the thing to watch out of the gate.

The splitter is Tanaka’s trademark pitch. He throws it more frequently (27%) than any he does any other pitch save his slider (29%), though that’s a little misleading. Before 2019, the splitter was Tanaka’s most consistent offering –and for good reason. Batters hit .196 (.230 wOBA) against it, with an average exit velocity of just 87 miles-per-hour. His whiff-per-swing rate was often near 40%. It was a truly elite pitch.

For example, here is a particularly strong Tanaka splitter from a July 2018 matchup against Ji-Man Choi in the Trop. The pitch clocked in at 87 miles-per-hour with a very high spin rate, and it made Choi look foolish:

We’ve seen that countless times over the years. However, the ball famously changed in 2019 – all of this historic success came crashing down. Tanaka lost movement on the pitch, batters hit it harder and farther, and they made contact against the pitch far more than normal. It was a mystery, especially at the beginning of the year.

“It’s the seams,” former pitching coach Larry Rothschild said in July. “I’ve thought that for quite a while.” For his part, it took Tanaka a while to buy in to the idea that it was not a mechanical issue. Nevertheless, he finally made a drastic change to his grip at the trade deadline. The results were stark. The Yankees may not have traded for a new pitcher at the deadline, but they got one anyway. Check it out:

1st Half.279.320.469.19024%89.3 mph1580 RPM
2nd Half.234.253.330.09631%87.9 mph1601 RPM
2014- mph1534 RPM

Obviously, it’s pretty clear that the pitch got much, much better. Given the difference in sample sizes, it was basically the same pitch it had historically been after it was borderline unusable in the first half. We covered this extensively here, here, and here, so check those out for more detail on the new grip, how the pitch lost its luster early on in the year, and how he got it back to normal.

Regaining the pitch helped him become more effective, as he pitched to a 3.79 ERA (3.70 FIP) with a 49% grounder rate in 61 innings from July 31 to the end of the season. Prior to the new grip, he had a 4.79 ERA (4.56 FIP) with a 47% grounder rate in 120 innings. (It’s only fair to note that there were two outlier starts in there skewing these numbers, but those starts count all the same.) Overall, this was a big difference, and the lesson is clear: an effective splitter makes Tanaka much more dangerous.

Now, this is not to suggest that the offering is his only good pitch. Far from it. His slider is also a lethal weapon – batters hit just .187 off the pitch in 2019 – that is good enough to carry him for stretches. I mean, look at this:

Devastating. Still, Tanaka is a low-velocity pitcher who relies on deception and complementary movement to be successful. He’s most effective when working low in the zone and lets the movement do the work. For example, check out this overlay GIF, courtesy of Pitching Ninja:

There’s more where that came from, but the concept is simple enough. Our man is not a flamethrower who can pump fastballs by hitters over the middle of the plate. He’s reliant on movement and pitch selection. As he gets older and his velocity declines – it hasn’t really yet but it will – then this will become even more important.

The old adage is that aging pitchers need to “learn how to pitch, not how to throw.” Tanaka, of course, already knows how to pitch: he’s been doing it since he came to New York. In over 1,000 innings since joining the Yankees, he has a 3.75 ERA (3.88 FIP) and 18 fWAR, and this doesn’t count his extraordinary October success. He’s been a very reliable and successful pitcher due to his ability to keep batters of balance and limiting free passes.

In other words, the formula for long-term success is already there. If he is able to show that the first half of 2019 was an anomaly for his trademark splitter, then I’m very confident he’ll be a steady presence in the Yankee rotation well into his thirties – and that begins tonight against Boston.


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1 Comment

  1. Mungo

    Tanaka has had issues with the Red Sox the last few seasons. Some lopsided games. Not entirely comfortable with him making his season debut with limited work against them, but he’s got to start somewhere.

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