PITCHf/x Forensics: Rich Hill and Blisters

Pitch forks have emerged, and rage has exploded over the most recent Rich Hill trip to the disabled list – once again, for a blister. Hockey fans gearing up for the playoff run scoff, stating how their sport has players who take slap shots to the face and return in the same game – blisters? Those are a sign that baseball players are weak, pampered, and fragile. Why do blisters keep forming on Rich Hill’s fingers? What are the implications for changing his style that could prevent blisters from occurring all together? Why can’t Sidney Crosby grow a beard? Let’s get into the answers to these questions.

All of pitching revolves around applying the appropriate amount of pressure to specific areas at ball release, and causing the ball to spin about a certain axis. This pressure applied along the seams, generates friction, and spin on the ball. More friction? More spin. That’s why pitchers try the ol’ Icy Hot trick to get a better grip on the ball, and throw funkier pitches. Sorry if I got most of my pitching knowledge from Rookie of the Year – I flamed out as a player in High School.

In review articles on the treatment of blisters in baseball players conducted by Dawson et al., (2004), and by McNamara et al., (2016), cited research indicating low moisture, and high moisture situations have the least amount of friction between the skin and the ball, but most skin increased frictional. Unfortunately, Statcast has let us down and doesn’t have a sweat leaderboard. This review also cited the concerns with blisters on the digits, as reducing control in pitchers, as well as reducing their velocity. The fluid filled “pocket” in a blister moves the surface of the skin away from the nerve endings – so, if the blister doesn’t pop – the pitcher will have reduced sensation of the ball in their hand at ball release. This would influence control and spin rates. The high friction associated with spinning a curveball would more than likely rupture the blister however, which then exposes a deeper layer of skin, and is extremely painful and delicate.

Dawson et al., (2004), identify 5 stages of blister development and treatment in baseball players. Unfortunately, in 3 of those stages, pitchers are recommended to not even touch a baseball. In a 4th stage, pitchers are instructed to pitch as much as tolerated – which is likely not enough to contribute as a pitcher on a major league roster.

So, why does this keep happening to Rich Hill? What risk factors in the realm of baseball are present that pre-dispose him to blisters?

The primary point of friction on a baseball during pitching occurs between the fingers and the seams of the ball – and from this gif of one of Rich Hill’s devastating curve balls, you can see that his fingers are positioned to spin the ball by the seams.


Spinning the ball faster theoretically would be a result of having higher friction on one specific area of the baseball during pitching (it isn’t as simple as this, but for the sake of this article, let’s just assume a linear relationship between friction and spin rate). Looking into the Statcast leaderboards on baseball savant, and pulling curve balls from all pitchers who threw a minimum of 150 curveballs since the beginning of the 2016 season, Rich Hill’s curve sits in the 95th %ile. Going back to my Stuff metric – Rich Hill separates his fastball and his curve ball by 24″ – which is in the top 10 of all pitchers (Table 1). His Stuff value sits in the 95th %ile – despite having a fastball that is lower than league average at 90.3 mph. Simply put, Rich Hill spins the hell out of the ball, and it’s a major part of what makes him an effective pitcher.


Break Distance
Break Rank Name Stuff Fastball Velocity Break Distance Change of Speed Breaking Pitch Velocity
1 Seth Lugo 1.53 92.5 25.3 15.7% 86.60
2 Kris Medlen 1.13 90.8 25.3 14.5% 84.80
3 Evan Scribner 0.98 90.2 25.1 20.4% 71.80
4 Jesse Hahn 1.56 93.9 25.0 19.7% 75.40
5 Aaron Sanchez 1.59 94.7 24.8 17.5% 78.10
6 Mike Fiers 0.96 89.4 24.8 17.3% 73.90
7 Rich Hill 1.50 90.3 24.5 17.5% 74.50
8 Rick Porcello 1.35 91.4 24.3 19.4% 85.10
9 Ricky Nolasco 1.24 90.4 24.0 19.1% 81.10
10 Paul Clemens 1.16 91.7 24.0 19.1% 74.20

McNamara et al., (2016) highlighted that force and repetition are the major contributors to blister development. The spin rates and break distances indicate that Hill likely has above average frictional force levels on the ball while throwing his curveball. When it comes to repetition – you can’t use total innings, or total pitches as a metric – because Hill is always hurt. However, when you look at it by pitches per inning – Hill sits in the 60th %ile (16.6 pitches/ inning) – meaning he throws more pitches per inning than 60% of all other pitches (who threw a minimum of 100 innings in 2016). His strike out heavy approach is partially responsible for this higher number.

So, why not just pitch through it? Why not take the hockey player mentality and tough it out? Recent research by Matsuo et al., (2017) examined finger movements around ball release during pitching, and discovered just how highly coordinated this action was. The finger tips are highly sensitive, and interference from blisters would have a major impact on pitcher control. Another line of questioning brought forth by Baseball Prospectus Toronto writer, Nick Dika, was why don’t pitchers just develop calluses to prevent blisters from occurring? Johannson and Vallbo (1979) performed studies that looked at finger sensitivity in different skin conditions – and calluses would reduce sensitivity.

Rich Hill figured it out late into his pitching career, by relying heavily on an other worldly curveball. His high spin rate and huge separation between pitches make up for a below average velocity fastball. Should Rich Hill try to spin the ball less in an effort to reduce blister development on his fingers? There is no guarantee he would be as effective of a pitcher if he did this. The reality is for fantasy owners – you may have to just get the quality out of the innings he does pitch, instead of pining for more innings of lower quality.


Matsuo, T., Jinji, T., Hirayama, D., Nasu, D., Ozaki, H., & Kumagawa, D. (2017). Middle finger and ball movements around ball release during baseball fastball pitching. Sports Biomechanics, 1-12.

McNamara, A. R., Ensell, S., & Farley, T. D. (2016). Hand Blisters in Major League Baseball Pitchers: Current Concepts and Management. American journal of orthopedics (Belle Mead, NJ), 45(3), 134-136.

Dawson, C. A., Bancells, R. L., Ebel, B., Bergfeld, W. F., & Mcfarland, E. G. (2004). Treatment of friction blisters in professional baseball players. Athletic Therapy Today, 9(3), 62-65.

Johansson, R. S., & Vallbo, Å. B. (1979). Tactile sensibility in the human hand: relative and absolute densities of four types of mechanoreceptive units in glabrous skin. The Journal of physiology, 286(1), 283-300.

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Ergonomist (CCPE) and Injury Prevention researcher. I like science and baseball - the order depends on the day. Twitter: @DrMikeSonne

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