Checkup: Felix Hernandez and PitchFX

We might as well start with the velocity concerns. Felix Hernandez’s declining velocity prior to this season led to a sequence of articles I wrote earlier in the year (here and here) about the King’s pitch repertoire. Virtually every pitcher loses steam on his fastball as he ages; that’s nothing new. The big question is whether or not Felix is capable of dealing with that velocity loss better than most. The fact that he is a sinker-balling pitcher, that he has multiple fastballs with different vertical movement, might just help him out. But first, it would be nice if his downward velocity trend took a break.

According to Brooks Baseball*, perhaps it has. In 2012, he threw his four-seamer at 93.2mph and his sinker at 92.4mph. This season, his four-seamer averages 92.7 and his sinker 92.2. The sample sizes are well into the hundreds at this point, and thus we can be pretty sure that he hasn’t lost much more than half-a-mph off his four-seamer, and just 0.2 mph off his sinker. Assuming the pitch velocity algorithm is consistent between 2012 and 2013, this is good news.

With that, let’s take a closer look at his pitch repertoire this season, ordered by frequency.

Sinker (33.6%)

Felix has thrown his sinker 33.0% of time this season, which is more in line with his 2010 and 2011 seasons (33.8%) than last year (26.1%). He uses the sinker similarly against both righties and lefties, and he will use his sinker in any count—ranging from 22% when he’s ahead to 47% when he’s behind in the count. That indicates that Hernandez uses his sinker more often when he’s playing catch up on a batter, and the difference in frequency makes sense since it’s not really a strikeout pitch.

Batters swing at it 44.3% of the time whiffing on just 11.3% of those swings, making the sinker his least elusive pitch. His sinker is basically a pitch-to-contact, get-me-out-of-this-at-bat kind of pitch. But that’s okay because when batters put it in play, they put it on the ground nearly twice as often as in the air.

Four-seam Fastball (22.9%)

Whether facing a righty or a lefty, Felix uses his four-seamer with similar frequencies in all counts. Where the sinker ranged from 22% to 47% usage depending on the count, his four-seamer range is much narrower—from 19% when he’s ahead against a lefty to 29% when he’s behind against a righty. Like many pitchers, Felix goes to his fastball whenever he feels it’s needed, regardless of the count.

With good control of his sinker along with high groundball rates, one might wonder why he uses a four-seamer at all. After all, his groundball rate flips on its head, with about 70% of all balls in play being line drives or flyballs. But what he loses in batted ball outcomes, Felix gains in slightly better control (3% less balls) and a better whiff rate (18.5%). Overall, his four-seamer generates strikes and foul balls an additional 7% of the time versus that sinker. Though I’m using just his 2013 data, his 2012 data is similar with respect to his fastballs.

It would also be fair to suggest that having two distinctly different fastballs makes each one a little better, but I’m not quite sure how to prove that, so let’s move on to the fun pitches!

Changeup (20.9%)

This comes as no surprise to Mariners fans, but I’ll say it anyway. This is one of the best pitches in baseball. Felix’s changeup clocks in at 89.5mph, faster than most changeups, but still about 3mph slower that his four-seamer and sinker. He throws it to righties and lefties alike, and as you’ve probably noticed, more often when he’s ahead and in two-strike counts.

Probably because batters are more often behind in the count when they see the changeup, they swing at Felix’s 61.6% of the time, whiffing at a staggering 42.5% of those swings and fouling off 32.1%. If a batter actually manages to put it in play, it’s almost always on the ground (68%). These are all good things, but this really sums it up: Felix Hernandez has ended 118 at bats this season with a changeup, and in those 118 at bats batters have produced a .203 slugging percentage. In 179 at bats last season, batters managed only slightly better at .251. Those are bad batting averages, let alone slugging percentages.

Obviously he’s throwing his changeup mostly in counts where batters are hitting defensively. But still, even in no-strike, one-strike, and full counts, Felix has allowed just a .304 slugging percentage in 253 at bats since 2010. It’s a damn good pitch.

Breaking Balls (22.6%)

Felix’s slider and curveball are mirror images of each other in that he throws his curveball almost exclusively to lefties and his slider to righties. He has figured out what sabermetricians have discovered across the league, that sliders have extreme splits and should rarely be used against opposite-handed batters. Unlike many pitchers, he doesn’t throw his breaking balls nearly as much in two-strike counts as in other counts—just 17.9% when he has a chance to record a strikeout, opting instead to go with that devastating changeup. Makes sense.

His slider and curveball have generated whiffs at 26.8% and 33.7%, respectively, a little less than his 30.9% and 36.3% rates from the last four seasons. Let’s not concern ourselves with the slight decrease in effectiveness, though, because his whiff rate on changeups has gone up, corresponding logically to him throwing more changeups in two-strike counts. That seems like a smart tradeoff to me.


We are seeing another effective season from the King, whether you look at ERA (2.69), xFIP (2.68), or jump into the nitty gritty of pitch-by-pitch data. As with many pitchers, he has played around with his pitch selection some during the last few seasons—trading four-seamers for sinkers and breaking balls for changeups in two-strike counts—but the end product is still one of the best pitchers in the game.


*Brooks and Fangraphs don’t always agree. The Fangraphs’ data suggests that Felix started throwing a cutter in 2012, but Brooks seems to think otherwise.  This from Fangraphs:

“While [Brooks’] classifications are often consistent with the data given to FanGraphs and available at Texas Leaguers, there are situations where the pitch types are different.”