CC Sabathia’s two-seamer and ground ball rateBy
On Thursday Mike penned an ode to CC Sabathia: workhouse extraordinaire. It was a piece that focused on Sabathia’s durability and consistency, praising him for his extremely high level of performance over an extremely high workload. It was also a piece that Sabathia himself tweeted from his official Twitter account. Pretty cool, eh? There’s one aspect of Sabathia’s game that has gone relatively underreported though, even though relative is a very loose term in the Yankee media world. The change is CC’s increased ability to get groundouts.
CC entered the league as a young buck, a mere 20 years old, and for the first three years of his career averaged a groundball percentage in the low 40% range. He bottomed out at 39.3% in 2004, a year in which he also registered the lowest GB/FB ratio of his career (0.96). In 2005 he saw his groundball rate jump to nearly 50%, giving him a career high 1.61 GB/FB ratio, but the numbers settled back in around 45% for the next three years before dropping to 42% in his 2009 campaign with the Yankees. 2010 was a different story. While his strikeout rate slid down to around 7.5 batters per nine innings he registered a groundball rate of over 50% for the first time in his career, a rate good for 4th best amongst AL left-handers and nearly identical to the rate of Phillies’ pitcher Roy Halladay.
It would be unwise to make too much of this, as this could prove to be a momentary blip in the radar like 2005. But there are some interesting questions as to how and why Sabathia ended up notching 70 more ground balls in 2010 than he did in 2009. Part of the explanation could be a slight change in repertoire. In 2007 and 2008 Fangraphs’ Pitch F(x) source shows Sabathia featuring primarily a four-seam fastball (around 60%), a changeup (18%), a slider (19%) and a curveball (averaging 2%). In 2009 though it started classifying some of those four-seam fastballs as two-seamer, and Sabathia registered a 3.1% for the two-seam fastball. In 2010 it saw an even bigger jump, and Sabathia registered a 14.0% two-seamer and just a 47% for the four-seamer. Texas Leaguers’ Pitch F(x) database saw something similar, showing Sabathia throwing a sinker 3.2% of the time in 2009 and 14.1% of the time in 2011.
So there are a few obvious questions. For one, is Sabathia actually throwing a two-seamer/sinker? Secondly, has he started throwing it more often recently? Thirdly, is it responsible for the uptick in ground balls? The answer to the first question is the easiest: yes. Aside from the support received from the Pitch F(x) database, Sabathia by his own admission throws what he terms a “two-seamer”. He mentioned it in 2009 when the Yankees acquired Curtis Granderson, stating that his approach to Granderson was “two-seamers in to keep him honest, then get him out away”. He also brought up his two-seamer as recently as last week, after the simulated game, saying that his two-seamer was “doing what it’s supposed to do”. This part of the equation is clear: Sabathia throws both a four-seam and a two-seam fastball.
Unfortunately, the answer to the second question is far more murky. We know that there are questions surrounding Pitch F(x) classification. In 2010 many pitchers saw increases in their two-seamer and cutter rates, a fact likely due to an alteration in the classification algorithm rather than a sudden league-wide change in repertoire. As Pitch F(x) guru Mike Fast put it in June of last year, “Ross has made significant updates to this algorithm every year, and one of the most noticeable impacts is that the percentage of pitches classified as two-seam fastballs has increased with each update. This does not mean that the pitchers themselves have changed anything about their pitch selection or the movement on their pitches.” Fast recommends examining the relevant velocity vs. spin charts for the pitcher so that it becomes possible to see whether a new cluster of pitches has emerged or whether the system is simply re-labelling an existing pitch as something new. Sabathia’s 2009 velocity vs. spin chart is available here; his 2010 velocity vs. spin chart is available here. Obviously there is a greater preponderance of sinkers in 2010 than there is in 2009, although that’s to be expected. We do know that the pitch is distinct from the four-seam fastball in both horizontal and vertical movement. It remains unclear, though, as to whether this constitutes a new (within the past two years) development or is simply the product of Pitch F(x) becoming more detailed and accurate about the types of pitches pitchers throw.
As such it remains difficult to answer the third question, whether this pitch is responsible for the ground balls. Sabathia certainly got more ground balls in 2010, so if Sabathia is indeed throwing more two-seamers then it would certainly provide a solid explanation for why his ground ball rate jumped over 50% for the first time in 2005. This will be an interesting question to monitor in 2011, and it would certainly provide clarification if a reporter could get CC to talk about his changing approach to hitters. Is he actively trying to get more ground outs? Is he accomplishing that goal by throwing more two-seamers? As he gets older, it will be harder and harder for CC to maintain the elite strikeout rates he’s managed in the past. If he’s able to adjust and compensate for that by getting more ground balls then he may find his longevity as an elite pitcher extended by a few years.