Hiroki Kuroda pitchF/X Diagnostic Check

You don’t need me to repeat it, but I will anyway: Hiroki Kuroda’s been an utter disappointment thus far, pitching at the replacement level, losing his control, and serving up long balls like it’s nobody’s business. And while eight innings of shutout ball against the Oakland Athletics last night may turn some heads, Kuroda’s still faces a problem where he hasn’t before. He can’t get anyone to swing and miss.

His eight shutout innings were mostly a function of some good fortune and a solid strike-to-ball ratio. That said, he generated only five whiffs on the night, which equates to a mere 4.8% of his 104 pitches on the evening. Over the first four years of his major league career, he’s generated swinging strikes on 9.9% of his pitches, while this year’s total is between two and three percentage points below that.

What’s the problem, then? Why are opposing hitters swinging less? It’s not mere coincidence – no, look no further than his walk rate for some answers.

The picture above shows how often each of Kuroda’s pitches is a ball in 2012, compared to his career totals. Each pitch is being clocked as a ball in 2012 – he’s missing the zone more, and opposing hitters are holding off as a result. There’s meaningful correlation with his opponents swing percentage, which is nearly 6% below his career total. Opposing hitters are asking Kuroda to throw strikes, and he’s failing.

But even in cases like the A’s start, where he was hitting his spots and harnessing his control quite nicely, his stuff isn’t up to par. The velocity is down – almost uniformly by one mile per hour or more across his five-pitch repertoire of a fourseamer, a sinker, a slider, a curve, and a splitter – and he seems to have lost trust in his fastball, which he’s throwing nearly 7% less of the time.

His fourseamer seems to be the root of the problem. In 2011, it was called for a strike 11% of the time and whiffed nearly 11% of the time otherwise, while it’s being called for a strike only 8% of the time this year and is being whiffed at only 9% of the time. The moral of the story is that for Kuroda to find the success he once knew intimately and consistently for four years, he’s going to need to regain that extra oomph on his fourseamer and trust it enough to pound the zone with it. Once he can throw it with confidence, the cycle of attacking with return.

He’s being conservative because his stuff has slipped, and maybe next time, the balls will fall for the A’s. Perhaps a mechanical adjustment is in order – it won’t work for too long in it’s current layout.

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