Jose Fernandez is a superstar. Few of us doubt his ability, even after undergoing Tommy John surgery. He pitched at a high level in seven games for the Miami Marlins last year, and there are many examples of great pitchers returning post-surgery to dominate competition (think Jordan Zimmermann, John Smoltz, Kerry Wood). However, 44 percent of pitchers who continue to pitch in the MLB after UCL reconstruction re-injure their throwing arms. We have to consider a scary possibility: is Fernandez injury-prone?
Fernandez already falls within the 44 percent - he injured his throwing arm last season after returning from his UCL surgery. Could there be more than meets the eye behind these injuries? I thought an interesting approach to this article would be to do a frame-by-frame comparison of Fernandez to two of the most durable and established pitchers in baseball: Justin Verlander and Felix Hernandez.
We can look for inconsistencies between the delivery of Fernandez and these pitchers to determine if there is a mechanistic basis for his injury. When taking a closer look, things become murky. It appears Fernandez suffers from something I discussed last week: early trunk rotation. Here is a reminder of the early trunk rotation definition from the 2015 Medstar study that discusses this mechanical flaw:
"Early trunk rotation was defined as trunk rotation before the stride foot hit the ground and occurrence of non-vertical arm position at initiation of trunk rotation"
Now, let's take a look at a frame-by-frame comparison of Verlander, Hernandez, and Fernandez side-by-side:
What I notice immediately is that Hernandez and Fernandez seem to have very similar deliveries. Verlander, on the other hand, has a classic overhand delivery that minimizes stress on the elbow and shoulder. A great way to analyze trunk rotation is to focus on part of the jersey to determine where the trunk is facing. What you notice about Verlander is he begins rotating his trunk after the plant foot has hit the ground and his arm is vertical. You can see this in frames two and three. This allows him to effectively transfer energy from his lower body into his throw, minimizing stress on the throwing arm. Now, let's take a closer look at Hernandez and Fernandez.
If you look solely at arm positioning, it appears that Hernandez and Fernandez have identical deliveries. But remember, focus on the jersey. In Hernandez's delivery, we can see the SEAT of Seattle up until the fourth frame, when he starts rotating his trunk towards home plate AFTER his plant foot has hit the ground and AFTER his throwing arm is in the vertical position.
However, Fernandez appears to rotate his trunk early and we see this in frames two, three and four. The MIA of Miami on Fernandez's jersey disappears to an M in the third frame and then it becomes completely unreadable in the fourth frame. It certainly looks like Fernandez is suffering from "early trunk rotation." Energy is ineffectively transferred to his arm, subjecting it and his shoulder to unnecessary rotational stress. Due to the poor energy transfer, it is also possible Fernandez is throwing with too much arm to generate that top end velocity.
There is a reason that Verlander and Hernandez have had such healthy, effective careers. From 2006-2014 Verlander pitched at least 186 innings per season and over 200 innings in eight of those seasons. Hernandez has pitched over 190 innings per season since 2006 and over 200 innings in eight seasons as well. It is more than likely that they both exhibit effective mechanics that minimize their injury risk.
What we saw above was evidence that neither of them suffer from "early trunk rotation," a mechanic flaw that has shown to significantly increase the risk of shoulder and/or elbow surgery. However, it appears that Fernandez exhibits this flaw. Could this be the reason for his injury history? It is telling that two of the most durable pitchers in the MLB do not exhibit "early trunk rotation."
Now, will I argue that poor mechanics are the only and definite reason Fernandez needed UCL reconstruction? Absolutely not - in fact the 2015 Medstar study showed that while 33 percent of pitchers who exhibited early trunk rotation sustained an injury requiring surgery, 23 percent who did not exhibit early trunk rotation also sustained an injury requiring surgery. Therefore, a significant number of pitchers who did exhibit early trunk rotation didn't suffer a serious injury.
However, Fernandez's throwing motion, combined with throwing arm overuse that likely began during his earliest baseball years, could continue to put him at significant risk. While he might have amazing stuff when on the mound, he could also spend significant time off of it. For the immediate future, expect Fernandez to shine. But I will always be sitting on the edge of my seat worrying about his health. I will be hoping that Juan Nieves and company can address these issues to develop a safer delivery for Fernandez in the future. Perhaps by looking at someone durable with a similar delivery, such as Hernandez, Fernandez can improve his mechanics to decrease his risk of re-injury.
Are you concerned that Fernandez is at risk of re-injuring his throwing arm? Let us know in the comments below.
Pictures of Verlander, Hernandez, and Fernandez were taken using QuickTime to convert MLB.tv video to frame-by-frame photos