The reemergence of Masahiro Tanaka’s fastball is a good sign for the Yankees

The prevailing thought about Masahiro Tanaka’s pitch arsenal is that he is a bit of a junkballer. He throws mostly offspeed and breaking pitches, while employing one of the lowest fastball percentages in the major leagues. It’s an approach that has worked out quite well for him throughout his six-year term with the Yankees

However, there’s been a little bit of a monkey wrench thrown into that strategy this year, as Tanaka has lost effectiveness on his trademark splitter this year. What was once his best pitch (and the one he threw most frequently) has become his worst pitch by FanGraphs pitch values. In turn, Tanaka has allowed more hits and home runs on his splitter this year than any other pitch.

“Losing” a best pitch would normally lead to a disastrous season from most other pitchers, but not the crafty Tanaka. While the prevalence of his excellent slider has helped offset the loss of his splitter, the development of another one of Tanaka’s offerings has also helped him continue to fool hitters despite not having his best splitter.

Tanaka is relying on his fastball more than he has in several years, and instead of getting pounded, his heater has been effectively fooling hitters in 2019. This increased usage and effectiveness on the fastball has helped Tanaka turn what could have been a shaky season into an All-Star campaign.

Because his splitter is getting hit so hard, Tanaka is throwing it seven percent less than he did last year. While his increased slider usage has somewhat taken the place of all those splitters, so too have his two fastballs. Tanaka is throwing his four-seamer 28.5 percent of the time this year, and his sinker 5 percent – that adds up to 33.5 percent fastballs. That’s still a significantly lower figure than most other pitchers, but it’s Tanaka’s highest fastball percentage since 2015.

There’s a reason why Tanaka didn’t throw many fastballs from 2016-2018. Over that stretch, it was his worst pitch, resulting in heaps of home runs. With his splitter no longer a top-notch option this year though, Tanaka had to try throwing his fastball more. Surprisingly, the results have been excellent.

Hitters are swinging and missing on 20 percent of Tanaka’s fastballs, which is the highest whiff rate batters have ever had on that pitch. He’s also using it aggressively in all counts – it has been his put-away pitch to 18.8 percent of batters, which is also the most he’s ever used the fastball in two-strike counts.

None of this would work if batters were squaring up his heaters. Instead, the .278 batting average against on his fastball is the second-best figure of his career. Hitters’ .454 SLG on the pitch isn’t exactly eye-popping either, but again, it’s the best of Tanaka’s career. Although Tanaka’s fastball hasn’t become a bona fide lethal pitch, it’s at least become a solid offering that he can trust, and one that he feels comfortable throwing to hitters in all counts in place of his flat, 2019 splitter.

If batters had previously squared up Tanaka’s fastballs, what’s different this year? He hasn’t added any velocity – if anything, he’s lost about one tick from his early years due to the natural effects of aging. Instead, Tanaka, ever the control artist, has succeeded by painting the corners with his fastball and not being scared to attack hitters inside. See below Tanaka’s 2019 heat map on his fastball versus his 2017 fastball heat map:

Notice how the one on the top is more spread out, concentrated on both corners of the plate? Predictability is never a good thing, particularly on a straight pitch. Tanaka has mixed up where he throws his fastball this year – there’s more orange on all sides of the plate, up in the zone, and for the most part, he’s stayed away from the middle-middle region.

Ultimately, the best version of Masahiro Tanaka moving forward is the one that has command and confidence in his splitter. However, Tanaka has still found success this year by refining his fastball. Now, imagine for a second if Tanaka gets back his splitter and can pair it with his dynamic slider and a confident fastball?

It might just be the best version of Tanaka we’ve seen yet.