Phil Hughes and effective velocity follow up

Last week in this space, I examined Phil Hughes. Hughes is having some relatively unexpected success in 2014, so it makes sense to evaluate what might be different. I used the concept of effective velocity to look at any possible changes in Hughes' strategy and their ramifications. I'll dive more deeply here this week.

Last week, I looked only at Hughes' four seam fastball zone distribution using data from Baseball Savant. I didn't actually look at any effective velocity values, or how batters are actually producing against him this year. This week, I'll be looking at average effective velocity values for all pitches by zone. First, I'll show you the actual effective velocity values, which I'll refer to as EV from now on, by Baseball Savant zone definitions. For a refresher, here's the Baseball Savant zone. It's from the catcher's perspective, and zones 1-9 are the strike zone.

In last week's article, I noted that Hughes was using the lower parts of the zone less and the upper parts of the zone more. Armed with these data this week, it seems that Hughes is throwing harder or utilizing his pitches differently to achieve higher EV values. Last week, I also came to the conclusion that Hughes was throwing more strikes by taking some of those upper out of zone pitches and transferring them to in-zone pitches. So, compared to his Yankee years, Hughes is throwing more strikes, harder strikes, and up in the zone strikes. He's turned it up to 11.

Seeing the EV values is great, but it's good to put them in context to gain a greater understanding of what they mean. Perry Husband, the man behind effective velocity, discovered through his research that there is a "danger zone" of EV values, which is between 87 and 93. Hitters perform much better when a pitch has an EV value in that range. How has Hughes done in relation to the danger zone?

Welp. Hughes looks like he's spent some time on the highway to the danger zone. He's living on the edge. But he's not going to stop believing in his ability to get hitters out. The effective velocity adjustment is less extreme inside the strike zone, so I imagine that the increase in the danger zone percentage is a result of Hughes throwing more strikes. He's still in the safe zone more than half the time.

Pitching is complicated. Another interesting finding of Husband's is that achieving a difference of at least 6 EV between pitches within a plate appearance is optimal for keeping hitters off balance. This is related to pitch sequencing, something we haven't quite figured out how to quantify yet, but it is possible to calculate an average EV difference between pitches. For Hughes in 2014, the average EV difference between pitches within a plate appearance is 7.9 EV mph. For Hughes in 2008-2013, the average EV difference between pitches within a plate appearance is 9.7 EV mph. Hughes might be varying his EV values less in 2014, but he's still above the 6 EV mph difference threshold to maintain effectiveness. I imagine that the lower difference in EV values is due to Hughes' increased usage of a cutter instead of a slider, which homogenizes his velocity distribution instead of spreading it. That could also explain the almost across-the-board increase in EV values in 2014.

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From an examination of Hughes in detail, we've learned that Hughes is throwing more strikes, higher strikes, and harder strikes, but he's still maintaining a good EV difference between pitches to keep hitters off balance. How is this affecting his production? The answer is some. Hughes doesn't really limit any production on line drives; he hovers around average. Hitters generally hit very well on ground balls against Hughes. Where there is a possible difference is on fly balls. In 2013, Hughes' production allowed on fly balls was 17% above average. In 2014, before his most recent start, Hughes' production allowed on fly balls was 30% below league average. Hughes had some other good years of below average fly ball production when he was a Yankee, but the .128/.299 BA/SLG line on fly balls this year is pretty ridiculous.

Whether he knows it or not, Hughes' strategy of throwing harder higher in the zone is following the principles of effective velocity. Hughes throws his fastball much more often higher in the zone than lower, and he increases his usage of his secondary pitches lower in the zone to keep out of the danger zone. Hughes no longer has the fear of a homer-prone park, and he can pound the zone with his fastball. All this adds up to elevate Hughes' game to ace-like performance.

. . .

A note about the EV calculations. An old article from Baseball Prospectus had specific values for each part of the zone. Baseball Savant's zone definitions differ slightly from Husband's definitions in that zones 11,12,13,14 encompass more area. There are some cases in which the EV adjustment could be positive or negative depending on which part of the zone the pitch was, but Baseball Savant's zone definitions don't allow that level of granularity. In those cases, I assumed an adjustment of 0, which may not always be correct.

Another note. I did not consult with Perry Husband about calculating these values, nor does writing about effective velocity represent an endorsement from Mr. Husband. Beyond the Box Score and I are not affiliated with Perry Husband.

All statistics courtesy of Baseball Savant and Baseball-Reference.

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.