A year ago, Hunter Dozier got his first real taste of the big leagues and it did not go well. In nearly 400 plate appearances, Dozier struck out a lot, walked very little, and did not run the bases well or add anything of value defensively. His calling card to the majors, and the tool that got him drafted in the top-10 in 2013, is his power, and he was merely average there. Dozier was below replacement-level a year ago, and at 27 years old heading into 2019, he looked like a replacement-level player with some upside as the weak side of a platoon. Instead, he’s been one of the best players in baseball for the first month of the season.

With seven homers, nearly as many walks as strikeouts, and a .364 BABIP, Dozier is riding a .337/.441/.663 slash line good for an American League-leading 189 wRC+. His 1.7 WAR is fifth in all of baseball behind only Cody Bellinger, Christian Yelich, Paul DeJong, and Mike Trout. This isn’t going to last. It can’t possibly last, but it is worth exploring how Dozier got here and the level he might settle in to once the magic wears off. Over at Royals Review on Tuesday, Shaun Newkirk discussed Dozier’s start and listed some reasons why he’s bound to slow down:

His BABIP is .371, far more north than his near league average BABIP of .296 last year. While good quality of contact can lead to better balls in play, .371 is probably a bit rich.

He isn’t a 194 wRC+ hitter. No one expects that number to continue as he’s not prime Miguel Cabrera, Mike Trout, or Barry Bonds.

The projection systems don’t necessarily buy it yet. They project him going forward (this includes what he has done in 2019 by the way) for a 93-97 wRC+.

He’s running a 20%+ HR/FB%, where the league average is more like 12-13%.

He’s at almost double the league average infield hit%, which isn’t a big part of his game to be fair.

He’s also yet to hit any any infield fly balls, whereas a typical batter hits ~10% of his batted balls on the infield

The focus of Newkirk’s piece isn’t on where Dozier’s numbers will eventually fall, but on the plate discipline that has helped his rise. Even a quick glance at the numbers shows how Dozier is different.

Hunter Dozier Plate Discipline Season Team O-Swing% Z-Swing% Swing% O-Contact% Z-Contact% Contact% Zone% 2018 Royals 35.2 % 66.7 % 50.1 % 49.7 % 88.2 % 73.9 % 47.3 % 2019 Royals 23.2 % 55.0 % 38.3 % 46.9 % 93.3 % 78.4 % 47.3 % Pitch f/x

The most important changes for Dozier have come outside the strike zone. He previously swung at 35% of pitches outside the strike zone; now he’s down to 23%. With the league average coming in at 29%, Dozier has moved from one extreme to the other. When he does swing, he’s still making contact under 50% of the time, which is below league average, while still making contact on pitches in the zone at an above-average rate. He’s still seeing the same number of pitches in the strike zone, but he has simply chosen not to swing at a lot of pitches, no matter where they are located. When asked about his newfound hitting philosophy by Sam Mellinger, Dozier gave a fairly simple, straightforward answer.

“Something I’m trying to be a little better at is really only swinging at good pitches,” Dozier said.

Dozier has always had tremendous raw power, with Eric Longenhagen putting a 65 on his raw power ahead of the 2018 season, though only an average 50 on his ability to get to that power in games. Even when he struggled last season, he did pretty well when he was able to make contact, putting up a .411 xwOBA on contact, which ranked 54th out of the 228 players with at least 250 batted balls. With an above-average 89.5 mph exit velocity and a middle of the pack 13 degree average launch angle, Dozier didn’t need help lifting the ball. He needed help making contact, and his new approach has been very successful.

Last season, Dozier saw more fourseam fastballs and sliders than any other pitches, and that has been true this year as well. He swung at 25% of fastballs outside the zone last season and had a 9% swinging strike rate on the pitch overall. This year, he’s swung at just 13% of fourseamers outside the zone, and his whiff rate on the pitch is down to 3%. But the more important gains for Dozier have come on the slider. The slider is a pitch that goes outside the strike zone around 60% of the time. Of those pitches out of the zone, Dozier swung at nearly half of them and made contact less than a third of the time, leading to an overall 23% whiff rate on all the sliders he saw last year. This season, he’s swinging at under 30% of sliders out of the zone and while he’s still whiffing a lot when he swings, the reduced swings have dropped his swinging strike rate on sliders by seven percentage points.

In terms of sustainability, Dozier has seen about 200 pitches outside the zone and swung at 23% of them. In looking at how reliable that number is, the 95% confidence interval for that rate and number of opportunities puts Dozier between 19% and 30%, a clear improvement over last season’s 35% chase rate. The way for Dozier to make more contact isn’t to shorten his swing, expand the zone, and try and make contact on tough pitches; it’s to try and ignore those tough pitches completely and focus on pitches where he can make good contact. In his piece on hitters this season, Eno Sarris talked to Adam Ottavino about how hitters are changing their approach and Ottavino said this:

“You’re seeing more of that Dodger-type approach: Get your A-swing off all three times but be really good at commanding the zone,” Adam Ottavino told me this week. “Selective, but powerfully selective. The old swing used to be to see the ball deep — so that you could take the fastball to the opposite field or catch the breaking ball out in front — but now people have now seen the Justin Turners of the world, where they are really selective, but when they get their pitch they’re ready to hit it early and out in front. If you get your A-swing off and it ends up being a bastard pitch, they’re okay with it because they’ll miss it and they’ll have another chance. Don’t put it into play weakly.”

My look at early season numbers indicates that more hitters do seem to be taking this approach by swinging at fewer pitches outside the zone resulting in more walks and more hard contact by swinging at pitches they can handle.

Hitters are swinging and missing on more pitches than they ever have before and that has meant strikeouts continue to rise, but they’ve stopped the bleeding when it comes to chasing offspeed pitches outside the zone as they see more and more of those pitches. The result has been more walks and more power, which has counteracted some of the gains pitchers have been making over the last few years.

Plate Discipline Revolution might not have the same cachet as Launch Angle Revolution–though it’s not like the latter exactly rolls off the tongue–but hitters can make huge advances by being more selective and taking big swings at pitches they can hit for power. We don’t yet know how this will play out for Dozier. He’s taking a lot more called strikes this year (21% of pitches) compared to last year (16%), and it is likely that approach will lead to more strikeouts. Dozier’s plate discipline numbers show he swings at few pitches generally and doesn’t make contact on pitches outside the zone. He doesn’t have a ton of close comps, but the closest might be Tommy Pham.

Like Dozier, Pham is fairly patient in and out of the zone, and when he swings at pitches off the plate, he doesn’t make a ton of contact. Also like Dozier, when Pham makes contact, he hits the ball hard. Pham has a career 12% walk rate and 25% strikeout rate with an ISO right around .200. If Dozier is going to keep his success going, that’s probably what it’s going to look like. Dozier isn’t going to keep this up at his current level, but his future looks far brighter than it did just one month ago.