The dimensions of New Yankee Stadium are a nuisance for pitchers. Especially for pitchers who face an abundance of left-handed hitters. According to ESPN, New Yankee Stadium is tied for ninth with Target Field in park factors on the season. Sorting by home run park factors, the Bronx jumps to sixth place, ahead of the notorious Coors Field.
Masahiro Tanaka's performance this season hasn't been as amazing as his debut last year. After posting a 2.58 xFIP, 0.99 HR/9, and an already-high 14 percent HR/FB rate, Tanaka has let all of those numbers slip to 3.25 xFIP, 1.63 HR/9, and 18 percent HR/FB rate. It's almost like playing in a hitter's park can be detrimental to a pitcher's statistics! In fact, it's probably all the New York architects' fault for building such a nonsensical right field porch, right?
Let's take a look at Tanaka's home run spray chart courtesy of Baseball Savant:
That's an awful lot of home runs to right field. In fact, some even look suspiciously shallow. Let's take a closer look at one such instance. Let's start with the one Chris Davis hit. It's the one that looks the most shallow, third from the left in that line of shallow dingers.
Just as we suspected. Wait. That ball was murdered. I didn't know if that ball was going to come down when I watched it the first time. An 89 mph cutter down the heart of the plate to Chris Davis? There's nothing that screams 'stupid ballpark' about this one. You don't leave that pitch there.
Well, that one didn't really work out. There must be others though. Let's move to the right by one in our spray chart and take a look at Kyle Seager.
That's another no-doubter that actually looks closer to centerfield than the Davis one. A 1-0 curveball down the chute. These are getting unruly.
Later in the same game, Kyle Seager did this:
Tanaka leaves a 92 mph sinker in Baseball Savant 'zone 4'. The other two that seem to be hit to shallow right field in the spray chart didn't happen at New Yankee Stadium. One is Derek Dietrick at Marlins Park and the other is Carlos Correa at Minute Maid Park. The one on the left of the cluster is an even-more decisive, second-decker from Victor Martinez.
It turns out none of these home runs seem to be cheaters. Not even one unlucky one that Tanaka can shrug off as 'maybe I shouldn't have chosen the Yankees.' Literally zero.
However, all of them do have something in common. They are mistake pitches. None of them are low in the zone (zones 7-9 by Savant), even the sinkers. In fact, per FanGraphs, batters have a .442 wOBA against Tanaka's sinker. That's 101 percent worse than the mean (by wRC+). Furthermore, one third of his home runs against (6 of 18) have come courtesy of the sinker, despite only throwing it 18 percent of the time. It seems like it's time for Tanaka to lean on other pitches or seriously work on locating his sinker down in the zone.
As Nicolas Stellini astutely pointed out over at Pinstripe Alley, Tanaka's partially-torn ulnar collateral ligament could have something to do with his inability to locate his pitches in the lower quadrants of the zone. Similarly, Stellini points to a league-wide surge in HR/FB rates. Offense in the American League East has never quite been an issue, but having to face the high-scoring 2015 Blue Jays certainly isn't helping.
The fact is, we should probably expect Tanaka's 18 percent HR/FB rate to improve, but it does seem like Tanaka's pitches -- at least the way they have currently been deployed over his 236 career innings pitched -- yield a higher percentage of home runs. So long as Tanaka can supplement his long-ball problem with a high strikeout percentage, perhaps he can continue getting away with some location issues. However, with teams starting to favor groundball pitchers, at the very least Tanaka's sinker will require some work. And we should probably calm down about the right field fence at New Yankee Stadium.
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Michael Bradburn is a Featured Writer for Beyond the Box Score. You can follow him on Twitter at @mwbii, or reach him at firstname.lastname@example.org