PITCHf/x Forensics: Shelby Miller

Poor Shelby Miller. After last year’s disastrous debut with the Diamondbacks, Miller was looking forward to getting back to his previous Cardinals and Braves form. The season started well enough – his spring training was filled with reports about his increased velocity, and how well he was pitching.

In my initial calculations of STUFF for the 2017 season – Miller was up from 0.56 in 2017, to 0.84 in 2017. That is a huge increase that shows great promise for turning a career around. But now – the dreaded third opinion from Dr. James Andrews, and the discovery of a strained flexor muscle, and a torn UCL, which could lead to Tommy John Surgery, or at minimum, a year off with rehabilitation.

What risk factors were present that could have lead to Shelby Miller’s UCL tear? Let’s look at the research.

Table 1. Known risk factors for UCL reconstruction from research.

The interesting thing about this analysis – is that the 2016 iteration of Shelby Miller has no risk factors that particularly jump out at you. He’s right in the moderate area for everything, save for pitches per game – but that value is quite comparable to every other starting pitcher, if not lower. At the same time, this is a case of the sum of all parts – a compounding situation where it’s death by 1000 paper cuts.

Miller broke into the league in 2012, and his Stuff has remained relatively stable since. The biggest change in his Stuff has been this season – and, I’ve tried to take into account the change in data by re-normalizing Stuff to only 2017 data, and subtracting 0.4 mph from the fastball velocity.

Figure 2. Shelby Miller fastball velocity and Stuff, 2012 to 2017.

2017 is clearly a change here – the velocity is up significantly, and that’s not really something that happens when someone gets older. There are a lot of variables in play that we can’t quantify – how quickly did Miller gain this velocity in the off season? What did his training regime look like?

Interestingly, it has been noted that Miller suffered a flexor muscle strain, as well as the UCL tear. Given the urgency that Miller and the Diamondbacks had in accelerating Miller’s return to good-ness, there is a chance signs of discomfort were ignored along the way. When a flexor-pronator muscle is strained, the tension that the muscle originally supported during pitching is now transferred to the ligament. If you’d like to know more about this – there’s a very interesting discussion on flexor-pronator muscle tears/strains on the “fixing pitchers” podcast – http://fixingpitchers.com/podcast/baseball-pitchers-ice-games/.

This is a very important note for young pitchers – do not ignore your body’s warning signs. If something doesn’t feel right, tell your coach and get it looked at by a doctor.

There are no red flags in this analysis for Shelby Miller – but had the strain been noticed a bit sooner, there is a chance he wouldn’t have torn his UCL.


Whiteside, D., Martini, D. N., Lepley, A. S., Zernicke, R. F., & Goulet, G. C. (2016). Predictors of Ulnar Collateral Ligament Reconstruction in Major League Baseball Pitchers. The American journal of sports medicine, 0363546516643812.

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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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Weird stuff! Especially the end where this is spun as an article for young throwers. I am also not a huge fan of implying that Miller’s injury may have been preventable. Maybe it could have been and maybe not, but I personally don’t like like implying that people’s misfortune is their own doing… unless it clearly is.