Fastballs, Tommy John, and Twins Pitchers Who May Be at Risk

The basic premise is that pitching at max velocity puts a pitcher at greater risk for damage to the ulnar collateral ligament (UCL). With increased focus on velocity, pitchers are throwing harder in shorter stints, leading to increased stress on the elbow (and ultimately surgery). Basically, pitchers with varied pitch mixes that are less fastball heavy are less likely to become injured.

According to a research study the injury threshold for fastball usage is at 48%. The researchers took group of pitchers who had undergone Tommy John and looked at each pitcher’s two seasons prior to the surgery. They found once a pitcher exceeds 48%, each additional percentage of fastball usage leads to a 2% increase in risk for UCL injury.

Of course there are undoubtably additional factors that put pitchers at risk for arm injuries. Twins Daily’s very own medical expert, Lucas Seehafer, did a great job of illustrating the roll proper mechanics can play in pitcher injury prevention and the increase of specialization at a young age has also been cited as a potential cause of injury. College and minor league pitchers have a much higher rate of Tommy John surgery than their MLB counterparts, which fits our narrative as they’re likely to be throwing a higher mix of fastballs and have less developed mechanics.

While I’m not at all qualified to break down mechanics for injury risk, I am capable of going over to Baseball Savant and looking through fastball usage to see who crosses the dreaded 48% fastball threshold. We’ll stick with starting pitchers as relievers have less varied pitch mixes and are therefore likely to throw a higher percentage of fastballs (which sounds better than admitting I’m too lazy to bother with relievers).

Before we jump in, one thing to consider is if all fastballs are created equal. Some pitchers throw both four-and two-seam fastballs and four seamers are generally thrown at a higher velocity. As apparent in the names, the pitches feature different grips but also use different amounts of finger pressure on the ball. It’s possible that two-seam fastballs could be less damaging due to less velocity which in turn could mean less effort and therefor reduced stress on the elbow.

I must also point out that the study alluded to earlier looked at the two seasons prior to Tommy John surgery and I’ll only be showing the 2019 numbers. We’ll start with the highest percentage of fastballs and work our way down.

Randy Dobnak – 59.2 % (Sinker – 36.5%, Four-seam – 22.7 %)

Dobnak definitely fits into the two-seam issue alluded to in the previous paragraph. He utilizes his sinker more often than the four-seamer and it’s significantly slower than his four-seamer (92.2 mph vs. 93.4 mph). Maybe that will save his arm?

Jake Odorizzi – 57.9%

According to Baseball Savant, Odorizzi hasn’t thrown a two-seamer since 2016, so he’s strictly a four-seam guy. He throws it quite often, and for good reason as it’s arguably his best pitch. Prior to 2019, Odorizzi spent his offseason at the Florida Baseball Ranch and it led to his fastball velocity increasing from 91.1 mph in 2018 to 92.9 in 2019. While the velo spike could be viewed as a cause for injury concern, Odorizzi was pretty healthy in 2019, and it’s possible that mechanical adjustments increased his velocity without causing additional elbow strain.

Jose Berrios – 55.5% (Four-seam – 32.2%, Sinker – 23.3%)

Berrios has had his second-half struggles and has lost a bit of velocity throughout his career but he’s been remarkably durable. Berrios has shifted from featuring his sinker more frequently early on to now leaning more heavily on his four-seamer, as has been a trend throughout baseball. He still throws his sinker a fair amount and it was a full mph slower than his four-seamer in 2019. As mention with Dobnak, it’s possible the sinkers might put less stress on his elbow.

Michael Pineda – 55.2% (Four-seam – 54.1%, Sinker 1.1%)

Previous injury is the best indicator of future injury and Pineda has had his fair share of injuries, including shoulder surgery that caused him to miss the 2012 season and Tommy John surgery that put him out in 2018. In his two seasons prior to his elbow surgery his fastball usage was just above 48% and it was at over 60% the year before his shoulder injury. Pineda will have had some extra rest due to his PED suspension so maybe that will help once he returns.

Rich Hill – 52%

Hill’s definitely in the “previous injury” club as he’s had both shoulder and Tommy John surgery and had modified Tommy John surgery this offseason. He’s been a two-trick pony for quite some time with the curve being his second pitch, and has thrown 55%, 58%, and 53% heaters for the past three seasons. Coming off surgery and at 40-years of age, it’s hard to know what to expect from Hill, but he’s been extremely effective when healthy.

Lewis Thorpe – 51.2%

Lewis Thorpe has already had one Tommy John surgery as a minor leaguer after the 2014 season and missed the 2015 and ’16 seasons in recovery (a case of infectious mononucleosis contributed to the length). His 2020 role is up in the air but the increased need for arms should help his cause whether out of the ‘pen or as a swing starter. His MLB sample size is fairly small and minor league pitch usage isn’t widely available, but he tops the 48% threshold based on what we have.

Devin Smeltzer – 45.9%

Smeltzer was another long shot to make the team who could benefit from expanded rosters in 2020. As was the case with Thorpe we’re dealing with a limited amount of innings, but Smeltzer has been healthy throughout his pro career and comes in safely below 48%.

Kenta Maeda – 37.4% (Four-seam – 33.7%, Sinker – 3.7%)

Finally, we can breathe a bit with Maeda. He’s been solidly below 48% for the entirety of his MLB career as he relies heavily on sliders and changeups along with his four-seamer and the occasional curve. In his four years with Los Angeles he also frequently shifted to a bullpen role so his inning totals are fairly moderate. Of course, by writing this I’ve cursed Maeda and his ACL is bound to explode. I’m sorry.

Again, this is just one potential tool for assessing injury risk and there’s obviously other factors involved including mechanics and genetics. Technology will likely play an ever increasing role in injury prevention as well with devices such as pitching sleeves being used to identify potential risk. It’s also worth pointing out that being above 48% fastball usage isn’t a death sentence (the majority of MLB pitchers are above 48%), but it’s an interesting and potentially useful way to view and possibly lower injury risk.

MORE FROM TWINS DAILY

— Latest Twins coverage from our writers

— Recent Twins discussion in our forums

— Follow Twins Daily via Twitter, Facebook or email