In 2011, when Mike Trout made his major-league debut, it was at home against the Seattle Mariners. In the final game of the series he had to face Felix Hernandez, and it didn’t go well. Twice he got ahead in the count but tapped back to the pitcher on 2-1 sliders. In his only other at-bat that day, he struck out looking on three consecutive pitches.

They’ll face again tonight, a common event. Trout has faced no pitcher as much as he has faced Felix. The two have matched up 42 times, and since that first game Trout has won the series decisively. He has a .395/.405/.632 line against Hernandez, which includes seven overmatched appearances in his rookie season, when Trout wasn’t yet the Trout we see now. From 2012 on, in 35 plate appearances, he’s hitting .452/.457/.742.

When head-to-head matchup stats come up, it’s usually a manager citing small and/or outdated samples to justify putting Don Kelly in the lineup. In that context, it’s easy to mock the way such stats are used—as though a batter’s BABIP over 25 plate appearances spread out over a decade could really be telling enough to base strategic decisions on. With Trout and Hernandez, it’s a different conversation. Nobody’s going to use these numbers to justify putting Trout in the lineup; he’s already in. And the stats—at least the 35 since last year—aren’t outdated, as Felix and Trout haven’t changed much in the past two years. But the sample is still small. Too small? Is there anything we can learn about this matchup from 35 plate appearances?

Or, more directly: Do these 35 plate appearances tell us what to expect tonight when they meet again? Having watched each of them this week, here’s what I found.

Is there a clear pattern to the way that Hernandez attacks Trout?
Yes, particularly early in counts. Here are the first pitches that Hernandez threw to Trout in each of his at-bats during the 2012 season:

Fastball, Fastball, Fastball, Fastball, Fastball, Slider, Fastball, Fastball, Curve, Slider, Fastball, Fastball, Fastball, Fastball, Fastball, Fastball, Fastball, Curve, Fastball.

Which isn’t super convincing—and, of course, there are different kinds of fastballs—but which is more convincing when paired with this: The target for every one of those fastballs was away, and generally low and away.

That’s not to say every pitch was low and away. Some pitches missed location, so if you were looking at the pitch charts the trend might not overwhelm you. But the target was always the same, on the first pitch and (to a lesser extent, but still striking) after the first pitch. And it seemed clear that Trout adjusted to this; when a pitch would come to the inner half of the plate, he seemed almost spooked by it, so expectant of an outside pitch was he.

Is there an apparent trend to the way Trout approaches Hernandez?
Yes, particularly in year one: Trout was almost single-mindedly focused on going the other way. These aren't nearly all of the examples, but they're a few:

A triple:

A low line-drive single:

A sacrifice fly to right field:

A single between the first baseman and the base:

If my count is correct, Trout hit 18 of 27 batted balls to the right of second base. Indeed, it sometimes felt like he was too interested in going the other way; on a couple occasions that Hernandez missed location in or surprised Trout with a secondary pitch, Trout still went the other way and popped the ball up to right field or into the seats on the first base side. And I'd sort of like to see how far he would have hit this ball if he'd turned on it; instead it was a fly out to the edge of the warning track:

Has Trout actually hit the ball hard against Hernandez?
Yes. This is not one of those situations where a couple bloop hits can overwhelm a SSS slash line. Trout had 14 hits against Hernandez in 2012 and 2013, and while not every one was scalded—there was a broken-bat line drive up the middle, a jam shot that he inside-outed to right field, a push bunt, a hard-hit grounder off the third baseman's glove—they were, by and large, hit hard. Further, he hit four line drive outs (out of seven total line drives). And the groundballs that went through weren’t completely random outcomes, as the Mariners (particularly in 2012) often played the infielders in a couple steps to cut off Trout’s speed. The two fly outs to right field seen above reached the edge of the warning track.




Are there factors that seem unlikely to be repeated?
Yes. While this is going to be a sort of unspecific assessment, it seemed clear to me that Hernandez often lacked his typically excellent secondary stuff. Unless there’s something about Trout that does this to him—which seems unlikely—we’re dealing with some fluky good fortune for the hitter.

When Hernandez did throw a crisp secondary pitch, he generally got a swinging strike from Trout:

Consider this sequence on Sept. 1, 2012:

Roughly half of the breaking balls I saw looked like the first, and roughly half induced swings like the second. Generally speaking, Trout didn’t have to deal with Hernandez’s best secondary stuff. Perhaps relatedly, he got a much steadier diet of fastballs: about 75 percent fastballs, compared to the 53 percent fastballs that Hernandez throws to most right-handed hitters.

Has Hernandez's plan of attack changed in response to previous matchups?
Maybe. In 2013, Hernandez started throwing a bit more frequently to inside targets (generally with success). He also started leading off more at-bats with curveballs and sliders, including on five of nine at-bats in the final three games in which these two have faced each other. Trout, meanwhile, also changed his approach in 2013, taking more pull-oriented swings instead of sitting comfortably on the low/away fastball and going the other way with it:

The best sequence for Hernandez in any matchup against Trout probably came on September 22, the first of two at-bats in the game (and the last time the two have seen each other):

  • First pitch: Sharp curveball, Trout swings and misses
  • 0-1 pitch: Fastball out of the zone; a rare high target for the pitch.
  • 1-1 pitch: A changeup at 89 in the dirt; Trout swings and misses
  • 1-2 pitch: A fastball out of the zone; the typical down/away target.
  • 2-2 pitch: Hernandez goes back to the location at 94. Trout swings and misses.

That strike-three pitch is one that Hernandez has thrown to Trout what seems like dozens of times over the past two years. Trout has been, if his body language, his swing, and his results are any indication, geared toward that pitch, and geared toward the opposite field. This time, though, Hernandez’s ability to throw a good curve and a good changeup made it harder for Trout to sit on it.

So, basically, here’s where we stand going into tonight’s game: Mike Trout has crushed Felix Hernandez in his career, which includes a high number of at-bats for this type of batter-pitcher split but a low number of at-bats for any sort of rigorous assessment. He hasn’t just collected hits; he has hit the ball hard. And he hasn’t just hit the ball hard; he has looked in control doing it. There’s a sort of internal consistency to the results, as Hernandez has had a clear plan and Trout has successfully had a clear counterattack to that plan. The counterattack, fittingly for Trout, matches up with his general approach at the plate. Further, it has been augmented by Trout’s own speed and strength, which have made it harder to defend his batted balls.

On the other hand, there are signs that Hernandez is changing his plan somewhat, and there are plenty of indications that Hernandez can beat Trout when he executes his secondary pitches well. Here's my assessment of where things stand between the two:

  • Felix really wants to work primarily down and away, primarily with hard stuff, to limit how much damage Trout can do;
  • Even if he executes that plan, Trout will zero in on that plan and beat him;
  • But if he has a sort of second plan going to keep Trout off balance, Trout can't zero in—and Hernandez can beat him. So even though 75 percent of Hernandez's pitches might be fastballs low and away, it's the exceptions that will actually dictate the outcomes.

Given what Hernandez likes to do with the ball and what Trout likes to do at the plate, I like the matchup to continue in Trout’s favor, but I’d be surprised if it were as lopsided—or even statistically noticeable—in the future.

Thank you for reading

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A classic matchup and at least something we'll be watching for the next 6 years on a regular basis. Great stuff.
Thanks for the analysis. Looking forward to this one on opening day.
They must have read this article and changed their approach. king Felix went in with a breaking pitch and Trout pulled it for a HR.