The NL Cy Young Showdown

It’s almost that time of year again, when individual hardware is bestowed on the best players in each league, complete with the requisite hue and cry from constituencies exhorting the merits of their respective choices. In general, I tend to not get too worked up about such things, but will dip my toe into such discussions when my interest is piqued. Last year, I thought that Felix Hernandez deserved to win a close decision over Corey Kluber in the AL Cy Young race. This year, the NL Cy race is a particularly interesting one, a three-way dogfight among Dodgers Zack Greinke and Clayton Kershaw and Cub Jake Arrieta. Today, let’s utilize the batted-ball data at our disposal and try to make a call on this exciting race.

For the two Dodger aces, this is not their first Cy Young rodeo: Kershaw has won the award in three of the last four seasons, and Greinke won one with the Royals back in 2009. As for Arrieta, well, this is the first time he has even pitched enough innings to qualify for the ERA title. Kershaw, 27, and Greinke, 32, were slam-dunk, top-half-of-the-first-round high school blue chippers. Though Greinke has had some unique roadblocks along the way to perennial excellence, there likely aren’t many scouts who’ve watched either him or Kershaw from the beginning who are very surprised by what either has accomplished in the game.

Arrieta, 30, on the other hand, was a humble fifth-round Oriole draft pick out of TCU in 2007 who had previously been drafted out of high school and junior college. His progress through the minors was glacial compared to his Dodger peers, and he was eventually, famously dealt from the O’s to the Cubs along with Pedro Strop in exchange for Steve Clevenger and Scott Feldman in the summer of 2013. Now Clevenger has done a nice job for the Orioles of late, but I’d still surmise that they would like to have a do-over on this deal.

Each year, I compile my own ordered minor league lists of top full-season-league position player and starting pitcher prospects based on performance and age relative to league and level. These basically serve as follow lists, with the orders then tweaked based on traditional scouting methods. Greinke was the #1 starting pitcher prospect on my list in 2003; Kershaw ranked in the top 12 in both of his minor league campaigns, peaking at #9 following the 2008 season, before he mastered the strike zone. Both the eye test and performance-oriented metrics such as mine were in agreement; those two were sure things.

Arrieta? He qualified for my list twice, ranking #127 following the 2008 season, and #54 after 2009. This marked him as a pitcher with promise, possessing the potential to remain in a major league rotation, but the star power that he has shown this season would have seemed a bit farfetched back then. He showed flashes of brilliance as an Oriole, especially when posting a strong 109/35 strikeout-to-walk (K/BB) ratio in 114.2 innings in 2012 that was hidden behind a scary 6.20 ERA. Still, his career ERA was pushing 5.50 when he made the move west from Baltimore to Chicago. Almost immediately afterward, Arrieta’s potential was unlocked, with dueling out pitches, his sinker and slider, quickly emerging.

Let’s take a detailed look at the 2015 performance of these hurlers, through Tuesday night’s games, by examining their plate appearance frequency and production by ball-in-play (BIP) type data. First, the frequency information:

Right off the top, it’s clearly apparent that these three are among the game’s K/BB royalty. All three have well above MLB average K and BB rates, a lethal combination. Arrieta routinely ran high BB rates in his Oriole auditions, but his control blossomed in 2014, when his K and BB rate percentile ranks of 96 and 44 were in the same ballpark as this year’s 93 and 39 marks. Greinke’s K rate percentile rank of 69 is actually quite low for him, narrowly better than his 2010 career low of 68, though his BB rate percentile rank of 13 also nearly matches his career low of 11 in 2009. As for Kershaw, he has never had a seasonal K rate percentile rank below 93, and this is his second straight season with a MLB-leading K rate and percentile rank of 99. After struggling with his control early in his career, Kershaw’s 2015 BB rate percentile rank of 18 puts him on track for his fourth season at 20 or better.

Prior to this season, Arrieta never really had a defined batted-ball tendency of any type, but he has emerged as an elite grounder generator in 2015. His grounder percentile rank of 85 places him near the top of the NL. Interestingly, Arrieta has broken through this year despite a fairly high line drive rate (68 liner rate percentile rank). Liner rates fluctuate more so than those of other BIP types, so one might expect some positive regression in the future. One word of caution, however: he has posted liner percentile ranks of 66 or higher in four of his last five MLB seasons. Might he actually be one of the relatively few hurlers who actually has a propensity for giving up liners? I wouldn’t bet on it, but it’s something to keep in mind moving forward.

Speaking of guys who give up liners, Greinke’s 2015 liner rate percentile rank of 35 actually represents a career low, by far. He actually allowed an above league average liner rate each year from 2009 to -14, and has clocked in at 82 or higher in three of the last four seasons prior to 2015. This season could well be the outlier. Greinke has never posted an extreme BIP profile in any regard; he showed a slight grounder tendency in the 2010-12 time frame, but has been pretty neutral before and after.

Unlike Arrieta and Greinke, Kershaw has never allowed many line drives. His liner rate percentile rank has been below average in five of the last six seasons, and was in single digits in two of them. On top of that, Kershaw has at times shown the rarest of BIP frequency abilities: he has simultaneously induced high numbers of pop-ups and grounders. His pop-up percentile rank was above average each year from 2009-14, as was his grounder percentile rank from 2012 to -14. In 2015, his pop-up rate percentile rank has dropped to 39, while his grounder percentile rank is at 74, matching its 2014 level. Still, this is an elite profile.

Frequency rates can only tell us so much; to fill out the rest of the picture, let’s get a read on the authority level allowed by each pitcher by examining their production by BIP type data:

The actual production allowed on each BIP type is indicated in the batting average (AVG) and slugging (SLG) columns, and is converted to run values and compared to MLB average in the REL PRD column. That figure is then adjusted for context, such as home park, team defense, luck, etc., in the ADJ PRD column. For the purposes of this exercise, sacrifice hits (SH) and flies (SF) are included as outs and hit by pitchers (HBP) are excluded from the on-base percentage (OBP) calculation.

You’ll notice the preponderance of numbers under 100 (league average) in the REL PRD (Unadjusted Contact Score) and ADJ PRD (Adjusted Contact Score) columns: specifically, every single number except Arrieta’s fly ball Unadjusted Contact Score. Not only are these guys K/BB aces possessing varying levels of BIP frequency excellence, they also suppress batted-ball authority to a fairly significant level.

Arrieta has actually been quite unlucky on fly balls this season; his 136 Unadjusted Contact Score is adjusted way down to 71 for context. Not only does he induce tons of grounders, they are also hit quite a bit more weakly than league average, though his 57 grounder Unadjusted Contact Score is marked up to 83 once adjusted for context. His overall Adjusted Contact Score of 81 on all BIP is narrowly the best among the three hurlers.

The most eye-catching item on Greinke’s line is his absolute throttling of fly ball authority. He has allowed a mere .100 AVG-.250 SLG in the air this season, for a 25 Unadjusted Contact Score, which is still stellar at 47 after adjustment for context. His liner (99) and grounder (94) Adjusted Contact Scores are much more, well, human, but his overall Adjusted Contact Score of 82 ranks only fractionally behind Arrieta.

Kershaw’s fly ball authority suppression has been almost as good as Greinke’s, with Unadjusted and Adjusted Contact Scores of 52 and 44, respectively. In addition to running a high grounder rate, Kershaw has also allowed weaker grounder authority than either of his peers (79 Adjusted Contact Score). His overall Adjusted Contact Score of 90 is a bit higher than theirs, in truth in large part to the inclusion of the actual results of batted balls that didn’t register on StatCast, on which he allowed more damage than either other pitcher.

Let’s add back the Ks and BBs to the context-adjusted BIP data and see where we are. Kershaw leads the pack with a 2.19 “tru” ERA, followed by Arrieta at 2.46 and Greinke at 2.56. That’s the order my gut would have placed them in, as well. In this particular instance, FIP has it pretty much pegged, though the race gets a little closer once Arrieta and Greinke’s slight BIP authority data advantage is factored in. There are still a few starts to go, but Kershaw’s lead is likely to hold up.

In any event, this is a race to remember, including two of the game’s recent greats, one (Kershaw) at the apex of his powers, and another (Greinke) showing slight attrition in his K rate and a heavy reliance on unsustainably extreme levels of fly ball authority suppression (factors which point to likely near-term decline). They’re joined by Arrieta, a late bloomer whose skill set is very, very real. If he can eliminate his liner rate weak spot, he could get even better moving forward. Let’s enjoy the show down the stretch, and into the postseason.