Before Sunday's start, Phil Hughes was having a relatively dominant season. His strikeout rate is up a tick, but nothing really significant. Where Hughes is different this year is in his microscopic walk rate and reduced home run rate. It's fairly easy to improve your performance when you suddenly cut your walk rate three-fold and reduce your home run rate by half. But we can go deeper.
Let's look at Hughes' plate discipline statistics. Hughes is getting more of basically everything; more swings inside and outside the zone, more contact, and his zone percentage has increased dramatically. It's fairly easy to improve your performance when you suddenly start getting more out of zone swings while simultaneously throwing more strikes. But we can go deeper.
The concept of effective velocity is not necessarily a new thing. The quantification of it is. This long-form piece helps explain what effective velocity is, but I'll give you a short description. Effective velocity, or EV, is the idea that a batter has less time to react to pitches that are up and in and more time to react to pitches that are low and away in order to hit the ball on the sweet spot of the barrel, which effectively adds or reduces velocity to a pitch. The more a pitcher can vary his effective velocity, the more successful a pitcher can be. It is generally understood that Greg Maddux employed this concept and was successful because of his intuitive understanding of it.
This is where Phil Hughes comes in. Hughes' peripherals are all good and happy, but there's another stat that's rather surprising. Phil Hughes is successful despite throwing his four seam fastball almost 60% of the time. It's not getting knocked around that badly, either. It's getting whiffs about 11% of the time. Opposing batters are hitting .274/.434 (BA/SLG) against it, which isn't that great. Considering that hitters know it's coming, it's not that bad. This is where effective velocity comes in.
Most pitchers attack opposing hitters low and away. Everything low and away. According to the effective velocity framework, throwing fastballs low and away actually decreases the velocity of the pitch. Hughes is bucking this trend. Hughes is actually attacking hitters up in and away; Hughes is a fly ball pitcher, so you really only need to look at his GB% to determine that he throws pitches up. But he's doing it more than ever this year. The tables below show the distribution of pitches by zone thrown by Hughes from 2008-2013 and in 2014 (data from Baseball Savant) against right handers and left handers.
The zone numbers are according to Baseball Savant and are from the catcher's perspective; the numbers 1-9 are the strike zone and follow the numbers of a keypad on a phone. Zone 11 is up and in to a right hander, zone 12 is up and away to a right hander, zone 13 is low and inside to a right hander, and zone 14 is down and away to a right hander. Zones 1,2,3,11, and 12 are defined as high*. Zones 7,8,9,13, and 14 are defined as low*.
*High and low zone definitions are my own.
As you can see, Hughes has increased the percentages in the upper zones and has decreased the percentage of low and away pitches. Against right handers from 2008-2013, Hughes threw about 1.9 high pitches for every low pitch. In 2014, it's just over two high pitches for every low pitch. A small increase. Against left handers from 2008-2013, Hughes threw about 1.8 high pitches for every low pitch. In 2014, that ratio has ballooned to 3.1 high pitches for every low pitch.
I said earlier that Hughes is throwing more strikes, which is true. It seems that Hughes, in addition to throwing more high pitches in general, is taking more of those high pitches located out of the zone and putting them into the zone this year, and it's paying off for him. Last year, Hughes allowed about 17% higher production on fly balls than league average. This year, Hughes is allowing about 30% less production on fly balls than league average.
There is another factor for why Hughes might be pounding the zone more. Hughes has a home stadium that suppresses home runs, so it's likely that he's less afraid to get beat by home runs. That's allowed him to pound the zone more, especially up and in where his fastball plays up due to an increase in effective velocity. He's generating a lot of weak fly ball contact in addition to reaping the rewards of an almost non-existent walk rate. The Hughes signing has worked out very well for the Twins.
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Kevin Ruprecht is a Featured Writer of Beyond the Box Score. He also writes for Royals Review. You can follow him on Twitter at @KevinRuprecht.