Exploiting Bottom of the Zone Amplifies Phils’ Dominant Curveballs

Last week I explored the Phillies’ pitching staff’s ability to make hitters chase pitches while keeping swing rates down on balls in the zone. The numbers are staggering, but how exactly are they doing it? The answer: their most potent weapon, the curveball, plays incredibly well off their location-based, non-overpowering fastballs.

Exploiting the bottom-most edge of the strike zone makes a lot of sense given the current make-up of the arms manager Pete Mackanin sends to the mound. The staff as a whole lacks the dominant velocity that allows some leeway when leaving balls up in the zone. Despite an average fastball velocity only better than the Angels and Astros, according to Statcast, opponents haven’t punished the Phils’ offerings up over the plate.

Opponents are slugging .494 (eleventh-lowest in the league) against Phillies’ fastballs up in the zone with middle tier .224 isolated power. The teams with the three highest opposing batting averages against fastballs up in the zone all rank in the bottom five in average fastball velocity. But the Phillies are the outlier.

As conventional strategy would dictate, the Phillies do hone in on the lower third of the zone. Just fewer than 16% of all their offerings come low in the zone, sixth-highest in the majors thus far, as do 15.27% of their fastballs (fourth-most). The Phillies garner the Screen Shot 2016-06-08 at 1.39.31 PMsecond-highest overall strike rate on low fastballs in the league.

Living low, away from the barrels of major league hitters, is always important. Just ask the MLB competition committee. In each of the last nine consecutive seasons, they have witnessed a new league-wide record high strikeout rate. Just weeks ago, the committee responded by deciding to raise the bottom edge of the strike zone.

This unique profile—surprising success with fastballs left up in the zone and a propensity for throwing heaters low for strikes—unlocks their most valuable weapon and their signature calling card: the curveball.

Effective curves either begin in the meaty part of the plate and dive toward the bottom edge of the strike zone, or they begin lower, projecting toward the bottom third of the zone before torpedoing into the dirt with near impossible rates of success for overeager hitters. That elevated strike rate on low fastballs keeps opponents honest, both forcing them to expect the knee-high fastball, a prototypical pitcher’s pitch, and priming them to swing at pitches down in the zone.

It is here that the 2016 Phillies have made their mark, striking out an MLB-leading 163 batters on benders, 65 more than the next highest mark, 98, posted by the Indians. That gap between the Phils and Cleveland is greater than the curveball-generated strikeouts of 21 major league clubs.

Sitting in second and third in the league, respectively, are Aaron Nola, 52 strikeouts punctuated by a curve, and Jerad Eickhoff with 44; that’s 61% of Nola’s punch-outs and 70% of Eickhoff’s.

Much has been written about the starting rotation in particular and their use of the curveball as a primary weapon this season. The starters throw the pitch almost two percent more than any other rotation in the bigs (21%), the third-highest single-season mark for any rotation dating back 15 seasons, when FanGraphs began tracking this data. Four of Philadelphia’s five starters (all but Adam Morgan, who rarely throws his curveball) rank in the league’s top 35 in curveball usage. Nola tops the bunch at 33.51%, sixth-most in the majors.

The effectiveness of the curves is even more noteworthy than their historically high usage rate. To fully Screen Shot 2016-06-08 at 1.39.35 PManalyze all meaningful curveballs, we must examine the lowest third of the strike zone and zones 13 and 14. This low, extended portion of the zone will be referred to as “LowEx”. Over 12% of all pitches from the entire staff are LowEx curves, 285 more than any other team.

Phillies’ pitchers hold opponents to the sixth-lowest batting average against LowEx curves, .150, with a slugging percentage of .253, more than 45 points lower than the league average. One contributing factor is likely the increased spin rate exhibited on their LowEx curves. The Phillies average curveball has the fifth-most spin of any team, and on LowEx pitches, it ranks fourth-best (increased spin on curves helps generate drop).

Unsurprisingly, given the poor offensive performance against this pitch, LowEx curveballs courtesy of Phillies’ pitchers generate the second-highest strike-rate of any team.

Nola’s 26.54% LowEx curveball rate, out of 1149 total pitches, is the highest in the league among pitchers who have thrown 1000 pitches this season. Nearly four of every five deuces he throws fall in that ideal zone. Jerad Eickhoff (seventh) and Jeremy Hellickson (eleventh) sit just below him, with Vince Velasquez in shouting distance ranked 21 in the league. The list of the top 10 LowEx deuce rates reads like a list of modern-day yakker royalty: Jose Fernandez, Collin McHugh (whom the Astros acquired in 2014 solely due to his curve’s supreme spin rate), Rich Hill, Jose Quintana, Adam Wainwright, Felix Hernandez.

No other team has two pitchers in the top 11 in LowEx curveball rate. The Phillies have three. No other team has more than two pitchers in the top 25. The Phillies have four.Screen Shot 2016-06-08 at 1.39.39 PM

Only six pitchers in the majors have had LowEx curveballs put in play 50 times or more; none have allowed a lower opposing batting average than Jerad Eickhoff. At .088 (5 for 57), less than one in ten LowEx curves put in play off Eickhoff go for hits. Not to be outdone, Nola ranks fourth with a .120 batting average against (11 for 92).

To see the full scope of the team’s curveball dominance, we must focus on just zones 13 and 14, where pitchers are most likely to fool hitters. For simplicity’s sake, I’ll refer to these as the “putaway” zone. Just 11 pitchers have boasted curves devastating enough to elicit at least 25 balls in play on putaway curves, including Eickhoff, Nola and Hellickson. The Cubs were the only other team with multiple representatives. Here’s the leaderboard:

  1. Jerad Eickhoff .000 (0-37)
  2. Jake Arietta .038 (1 for 26)
  3. Jose Fernandez .045 (3 for 67)
  4. Adam Wainwright .063 (2 for 32)
  5. Jon Lester .077 (2 for 26)
  6. Aaron Nola .085 (5 for 59)
  7. Rich Hill .088 (3 for 34)
  8. Corey Kluber .091 (3 for 33)
  9. Gio Gonzalez .129 (4 for 31)
  10. Jose Quintana .143 (4 for 28)
  11. Collin McHugh .160 (8 for 50)
  12. Jeremy Hellickson .242 (8 for 33)

No soul that dared to put one of Eickhoff’s putaway curves in play reached safely. Just five of 59 against Nola reached base.

To put this off-speed dominance in perspective, I enlisted the help of FanGraphs’ pitch value metric, wCB, which calculates the average runs saved using a curveball aggregated throughout the season. This means that a good curveball used often will result in a higher rating than a good curve used sparingly. Because it is cumulative, wCB is affected by increased usage.

The Phils’ starters have posted a 20.7 wCB combined through 59 games in 2016. The next highest rotation wCB is Cleveland’s 10.3. If the season were to end today, the Phils’ rotation-wide wCB would rank 22nd-best since 2002 (when FanGraphs created the stat). Given that pace, their season-long wCB projection is 56.8. The best mark ever posted was 30.9 by the 2003 Cubs, headlined by Mark Prior, Kerry Wood and Carlos Zambrano.

As was the case in both of my previous two posts here at Crashburn Alley, and the majority of stories chronicling this young pitching staff, Nola separates himself from the pack. His 2016 wCB of 11.0 is by far the best in baseball (Eickhoff ranks third at 6.9). Such a gaudy figure, through just 59 games, puts the newly minted 23-year-old on pace for a season-long wCB of 30.2. That would be the highest single-season wCB posted in the 15-season history of the metric.

While the wCB pitch value metric isn’t predictive, the prospect that through 12 starts, Nola’s curve is projecting as the best in the majors over the last decade-and-a-half is perhaps the most stunning indicator of his early success. The gem of the rotation with an Uncle Charlie years beyond his age, Nola’s maturity has helped establish the low-in-the-zone identity of this young rotation.

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1 comment

  1. David

    June 09, 2016 02:28 PM

    Thanks Ben. Great insights.

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