Is Felix Hernandez Hurting?

Fresh off of the worst start of his career, Felix Hernandez is in the rundown for every baseball show on television. Often so far, the producer’s notes have asked the analysts to wonder if the team left their ace in too long, and what that means about the relationship between the player and his management and coaches. Here’s another reason to wonder if he was left in too long: is he hurting?

The science of injury detection and prevention is inexact to say the least. Otherwise our favorite pitchers would be having better luck staying on the mound than they are. But analyst Josh Kalk, before he was snatched up by Tampa’s Rays, once showed us that it might be possible to use PITCHf/x data to notice that a pitcher was in the injury zone: hurting before that pitcher himself would admit that anything was going wrong.

Using that same approach, it looks like the Mariners should have a sit down with their pitcher.

First, in table form, let’s look at the factors from the most boiled-down way possible: velocity and zone percentage. Velocity was cited as Kalk’s most important variable, and Noah Woodward found the same when he revisited the analysis. Let’s look at Hernandez over his career, in 2014, in 2015 as a whole, and the last three starts for comparison.

Key Injury Factors for Felix Hernandez
Period Velocity Zone%
Career 93.9 50.2%
2014 92.5 44.3%
2015 92.0 45.0%
August 92.4 47.0%

Nothing stark here. But if you add in release point consistency, and look more closely at this season, things start to really pop.

Over at Baseball Heat Maps, Zimmerman has enshrined the Pitcher Injury Factors for our use. Run Felix Hernandez over the last two years, and you’ll see a different story emerge.

First, the King’s velocity has been down all year, and his in-season bump looks nothing like what he saw last year and falls short of the one tick on the gun pitchers are supposed to get between April and August.


Perhaps Zimmerman’s zone numbers are drawn from Baseball Info Solutions’ zone numbers, because they look a little different. But those numbers mirror PITCHf/x both generally and specifically — and the game-to-game trends here are fairly clear: fewer pitches in the zone. (And a specific downturn after Hernandez rolled his ankle in a game on June first, as a few readers have pointed out.)


Lastly, we come to release-point consistency. His release points are generally less consistent then they were last year.


And, even worse, those release points are less consistent late in the game.


So maybe something worse than just normal aging is happening under the hood. It’s rare to see all four factors line up like this, and there’s enough smoke here to at least poke the embers to see if there’s a fire.

What’s worse is that, in that last start, these weren’t just embers. It was a roaring fire. Let’s revisit that table from above, but replace August with his numbers from the last start.

Injury Factors for Felix Hernandez (Including Last Start)
Period Velocity Zone%
Career 93.9 50.2%
2014 92.5 44.3%
2015 92.0 45.0%
Last Start 90.9 42.4%

A few not-so-fun factoids about that Saturday game. That velocity is the fourth-worst single-game number of the year for Hernandez, right when he should see peak velocity. Only twice before in his career has he had a velocity this low after May 15th.

The release point was all over the place Saturday. When seen in aggregate, his vertical release point data was the 164th lowest of the 278 games for which PITCHf/x has data, so it wasn’t egregious. But look at the release point consistency graph above and you can see that it was a wild game.

Hernandez threw a four-seam fastball to Brock Holt for a strike in the second inning. That’s on the left. He threw a four-seam fastball to Alejandro De Aza for a strike in a third inning. That’s on the right. PITCHf/x says the release point on the second pitch — similar to the first in terms of type and outcome — was a whopping 6.33 inches lower.


Despite the fact that it looks like there are trends in the data and Felix Hernandez is showing the traits that injured pitchers have shown before, we won’t know until he tells someone or the team finds something. But there was definitely something going on Saturday against the Red Sox, and the team could easily have seen the velocity and release point issues Hernandez was having.

At the very least, the King was hurting that day. And he probably shouldn’t have faced another batter after he hit Pablo Sandoval and then allowed Alejandro De Aza to homer to make it 7-2 in the third inning. And not because of his emotional relationship with his manager.

With a phone full of pictures of pitchers' fingers, strange beers, and his two toddler sons, Eno Sarris can be found at the ballpark or a brewery most days. Read him here, writing about the A's or Giants at The Athletic, or about beer at October. Follow him on Twitter @enosarris if you can handle the sandwiches and inanity.

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Logan Davismember
8 years ago

Today at the Rangers ballpark Felix was moving around on a mini-Segway instead of walking. Earlier in the season, on a muddy mound, he tweaked his ankle and had an awful outing; it apparently lingered for a couple of starts. At this point I think the mostly likely outcome is that he’s pitching through a lower body injury.

Chris from Bothell
8 years ago
Reply to  Logan Davis

Yep. June 1st. Safeco grounds crew didn’t get the roof closed in time and the mound was a mess. If you split his season stats as pre-June 1 and post-June 1 I think you can see an argument for that being the turning point (for the worse) for Felix’s season.