Future generations may judge us for not devoting enough attention to the near-miracle of Mike Trout, but we’re gradually making amends. Late last season, a subset of BBWAA voters decided that Trout had been the Most Valuable Player in the American League, despite his team’s fourth-place finish. In early April, MLB Network aired a documentary about Trout, part of a retrospective series that had never before focused on a single active player. A week after Opening Day, For the Win’s Ted Berg began a series called "Mike Trout Monday," whose founding principle was the notion that "the people need to know about Mike Trout." And later last month, when FiveThirtyEight’s Neil Paine debuted a weekly baseball column called "Full Count," he included a subsection called "TroutBeat," a feature designed to combat the tendency to take Trout for granted.
These developments all seem to send the same message: that while Trout may not be seeking stardom, he’s always newsworthy, anyway. If you’ve consumed much Trout content, you’ve probably read that he had the highest career WAR through an age-24 season of any player in history. If he keeps playing at his career-average pace, he’ll finish this year with the highest career WAR through an age-25 season (and with more than 50 fewer games played than the previous leader, Ty Cobb).
Despite a hamstring injury that cost him a combined six games — the longest regular-season injury absence of his professional career — Trout leads all position players this year in Baseball Prospectus WARP and both Baseball-Reference and Baseball Gauge WAR, with only Bryce Harper’s slightly higher FanGraphs WAR standing between Trout and a clean sweep of the win-value metrics. Only Babe Ruth has ever led his league in WAR in six consecutive seasons; Trout looks likely to tie him after his first full six seasons. Name a captivating player whose unprecedented stats this season have led to a deluge of articles — Aaron Judge, Eric Thames, Miguel Sanó. Trout has been better than whichever player you picked.
Trout has achieved his historic consistency through a remarkable ability to evolve. Throw him high fastballs designed to elude his low-ball swing, and he’ll eventually become one of the best hitters against that pitch. Tell him his arm is weak, and he’ll work on throwing until his arm is no longer a liability. Point out that he’s stopped stealing bases, and after combining for 27 in two years, he’ll swipe 30 in a single season. We’ve seen Trout stand out as an all-around stud capable of combining best-in-class baserunning and defense and back-to-back top-five finishes in the batting-title race. We’ve seen him excel as more of a strikeout-prone, home-run-happy slugger who once finished tied for fourth in baseball in dingers. We’ve seen him lead the majors in walks. However he’s gotten there, Trout has always ended up about 70 percent better than a league-average hitter.
His latest evolution suggests that he could be even better than that. The Trout we’ve seen so far this season has combined the best of all previous Trouts. He’s hitting for more power than ever before, on pace for his highest home run total. He’s striking out less often than ever before, despite another leaguewide rise in strikeout rate. He’s among the top 20 hitters in walk rate. He’s even moving well, ranking in the top 10 in baserunning value with eight steals in nine attempts and his highest-ever rate of extra bases taken. He’s been more than twice as productive at the plate as the typical hitter, and he hasn’t just benefited from lucky batted-ball placement: Trout’s BABIP, .360, is exactly in line with his career average.
Instead, Trout has gotten aggressive in a good way, continuing (and even accelerating) a trend he started last season. Trout’s overall swing rate is the highest it’s ever been, but his rate of swings at pitches outside the strike zone is either at its nadir (according to Baseball Prospectus) or very near its nadir (according to FanGraphs). Almost all of the uptick comes from an increase in swings at pitches inside the zone. At no point in his career has Trout swung at strikes this often over so long a span.
This is even easier to see on heat maps of Trout’s swing rates by pitch location. The GIF below juxtaposes Trout’s swing rates in 2015 with his swing rates this season. The darker red shading in the 2017 image indicates that Trout has started swinging much more frequently in those central regions.
Just two years ago, Trout swung at pitches directly down the middle a little more than half the time. This year he’s swung at more than 80 percent of such pitches. A large part of the increase in Trout’s overall swing rate stems from his much less passive approach on the first pitches of his plate appearances. Trout started out as a statue on first pitches, but this season he’s swinging almost as often as a league-average hitter.
In 2014, Sam Miller noticed that Trout almost never swung at first-pitch curveballs. Pitchers and advance scouts noticed, too, and started throwing them more often against him. It didn’t actually help them, on the whole — it’s hard to locate curveballs for strikes, so when pitchers threw them, they missed more often than not, which put them behind in the count. Trout actually did better in plate appearances that began with curveballs, even though he was essentially surrendering a strike to anyone who could get a pitch over the plate. In theory, though, taking every first-pitch curveball made Trout more predictable, and thus more exploitable, given the right circumstances.
Nowadays, he’s not so predictable. Trout still takes most first-pitch curveballs, but not all of them. Make a mistake and center one, and he’ll help himself to a hack.
There’s one more way we can look at this. A few years ago, I used plate-discipline stats to measure the approach many hitting instructors preach: "selective aggression," or swinging at hittable pitches while letting the bad ones go by. A high swing rate on in-zone pitches, coupled with a low swing rate on out-of-zone pitches, suggests that a hitter has a decent sense of the strike zone. (Unsurprisingly, the hitter with the highest ratio of in-zone swing rate to out-of-zone swing rate this season, based on Baseball Prospectus’s data, is OBP artist Joey Votto.) We can use this "selective aggression" stat to chart the development of Trout’s plate discipline and compare him to his peers who’ve seen at least 1,800 pitches in each of his previous seasons and 475 faced this year.
In his first, brief exposure to the big leagues, Trout’s selective aggression ranked in the first percentile compared with qualifying hitters. He swung at fewer than half of the pitches he saw in the strike zone and almost a third of likely balls, showing relatively little ability to differentiate between pitches he could punish and pitches even he would have a hard time driving. His ratio improved in 2012 and again in 2013 and 2014 before regressing in 2015, when he was probably playing through a wrist issue. Last year and this year, his strike zone judgment has made further strides, to the point that he’s now in the 94th percentile — one of the game’s smartest swingers.
Having a strong feel for the strike zone isn’t the only ingredient of offensive success: Plenty of hitters have the ability to distinguish balls from strikes but lack the coordination and power to make the most of that skill. But when a hitter with Trout’s physical gifts adds elite discipline to the mix, pitchers can’t counter. Thus far, they’ve thrown fewer pitches in the strike zone to Trout than ever before, but he’s not biting on bad pitches. Over the course of his career, Trout has produced a .465 weighted on-base average when swinging at pitches inside the strike zone and a .250 wOBA when swinging at pitches outside the strike zone. It makes perfect sense that he’d be even more potent now that he’s swinging at the former pitches more often and the latter less often.
It’s not abnormal for a young hitter’s plate discipline to improve. Even average hitters tend to cut back on bad swings as they play through their 20s (although they don’t tend to swing at more strikes). As Trout told Los Angeles Times columnist Dylan Hernandez this week, "Over the five or six years, you get to see pitchers more often and see their tendencies." Trout has been in the big leagues for years now, and he’s harder to fool.
But Trout has never been normal. Most players improve after age 20, sure. Even the average phenom who produces in the majors at an early age follows the same peaking patterns as regular players. When you’re the best 20-year-old ever, though, there’s no road map. It could have been the case that Trout was so good, so young, because all of his maturation arrived early. Instead, it looks like he still had room to grow. The best young player ever is, at least for now, getting better by the day.
Even Trout can’t stay on an incline forever, no matter how hard he works. At some point, his offensive skills will start to slip — the hamstring strains will become more common and more costly, and the swing will slow. When that happens, though, a less tooled-up Trout could compensate by digging into data he thus far hasn’t had to use. In the same conversation this week with Hernandez, Trout dismissed the utility of both batted-ball stats and video of opposing pitchers, saying "I like to be simple." To this point, the simple approach has worked extraordinarily well. When, years from now, it stops working so well, he’ll have information to fall back on, a rich resource that most players have to tap at an earlier age.
For now, we’re the ones obsessing over Mike Trout’s stats, using them to decipher what he’s doing on instinct and skill. Here’s hoping it will be a while before he has to study stats, too.
All stats current through Tuesday’s games.