Eric Thames is, at present, the major-league leader in wRC+. He’s also the major-league leader in home runs, and he’s the major-league leader in WAR. He’s gone deep in, what, five games in a row? That would be easy enough for me to fact-check, but I don’t want to waste my time checking those facts when Thames might extend his own streak at any moment. He’s homered in many games in a row. Let’s unpack what’s going on.

Literally yesterday, Nick wrote a post here entitled “Eric Thames Is Still Mashing.” That post spoke of Thames’ considerable power. Literally hours ago, Dave wrote a post here entitled “The Even Scarier Eric Thames Stat.” That post spoke of Thames’ seemingly improved ability to make contact. Power? Check! Contact? Check! What’s something that might drive both those things? Right — swinging at the correct pitches. At this writing, Eric Thames has baseball’s third-lowest swing rate at pitches out of the zone.

Just about every post written in April comes with an implicit or explicit understanding that, hey, it’s April. The reality is that not only is it early, but big-league pitchers are having to figure Thames out all over again. I’m willing to bet everything I have that Eric Thames won’t finish with the greatest single season in baseball history. Why, I bet he’ll even lose at least a hundred points off his wRC+. There will be games without Eric Thames home runs, and, dang it, I bet there might even be weeks. It’s a maddening sport, and even the best players look mortal for extended stretches at a time.

So, it’s early. I just want to make sure we all recognize something. By our numbers, Thames this year has seen 206 pitches, half of which have been out of the zone. He’s swung at roughly 16% of them, which works out to 16 swings in 103 chances. When Thames was in the majors before, he swung at about 34% of pitches out of the zone. That would work out to 35 swings in 103 chances. That’s 19 missing swings at balls, already. You can see why stats like this reach a stable point sooner than other numbers do.

Time for the trusty percentile rankings. I considered everyone who batted at least 250 times in 2011 and in 2012. Then I considered all qualified hitters so far in 2017. Below, you see Thames’ percentile rank in O-Swing%. You also see Thames’ percentile rank in Z-Swing% minus O-Swing%, which is another rough measure of discipline.

In the past, when it came to chasing out of the zone, Thames ranked in baseball’s worst quartile. So far this year, there’s been hardly anyone better. And in the past, when it came to swinging at the right pitches, Thames ranked in baseball’s lower half. Once again, so far this year, few hitters have been better. Eric Thames hit for occasional power in the majors, but he struggled enough to end up in South Korea. There, he earned himself the nickname “God.” The Brewers liked what they saw in his numbers, and Thames has already more than earned what he’s getting paid for this season. He could be worth the whole three-year contract by Memorial Day.

Plate discipline affects everything. A hitter with outstanding discipline still needs to have a good enough swing to punish hittable strikes, but discipline is crucial. A hitter who swings at more of the right pitches will make more contact. Said hitter will also make *better* contact. To give you a further idea of what this means for Thames, here’s a plot of his rolling big-league-average O-Swing%:

As with anyone, Thames has had his ups and downs. Even Joey Votto will have stretches where he expands a little too much. But while 12 games is a very small sample, Thames has never had a 12-game O-Swing% close to as low as where he is now. He’s still swinging at plenty of strikes, but balls have been sailing right by, un-offered at. For a visual idea of where the swings are, and where they aren’t, here’s some help from Baseball Savant:

Thames bats left-handed, to the right of these strike-zone boxes. You can see that he still likes to swing at pitches middle-away. It’s clear enough from these plots that that’s Thames’ hot zone. He covers the outer edge very well. But now look around the black box. Thames has barely chased up. He’s barely chased up and away. And he’s dramatically cut down on his swings at pitches below the knee. That’s where so many of these hitters are exploitable — they chase offspeed stuff in or around the dirt. Thames hasn’t done that, perhaps as a result of facing so much offspeed stuff in the KBO. His swing selectivity to this point has been among the very very best.

It’s certainly true that Thames hasn’t faced a sequence of would-be All-Stars. The other day, for example, he was fortunate enough to face Bronson Arroyo. Yet Thames is still outstanding even just in a Brewers context, and I’ll note that of his seven home runs, five have been hit in two-strike counts. He punished Tyler Chatwood. He punished John Lackey. He’s doubled against Marcus Stroman and Jake Arrieta. A player can’t conclusively prove himself in two weeks, but Thames is answering questions with every at-bat.

For a few more visuals, here’s a side shot of Thames before hitting a home run in 2012:

Here’s a side shot of Thames before hitting a home run in 2017:

The hands have gotten a little bit lower. Among whatever other changes Thames might’ve made along the way, he’s reduced the length of his bat path. When he swings, his hands go almost directly to the ball, with very little load. Picture someone like Josh Donaldson, and you see that exaggerated leg kick and coil. Thames generates just as much force, but he does it almost quietly, and it happens in the blink of an eye. There’s no real leg kick. There’s no real coil. Thames is just obnoxiously strong, and his power swing is nearly effortless.

Thames doesn’t need much time between the swing decision and the contact point. If his bat path is indeed shorter, that would cut down on his swing time even further. What that means is that Thames could afford to be more patient, watching pitches for an extra split-second. That’s a big part of what plate discipline is — maximizing your information before making a commitment. Whether for that reason or another, the Eric Thames we see today is armed with better decision-making. He’s always been one of the strongest players, even back when he was mediocre. When you’re that strong, you can afford to make your swing simple. Thames has a simpler swing, as well as a more experienced one. Adjustments will take place, because Thames is so much of a terror, but if he maintains even a fraction of this April selectivity, the Brewers are going to be ecstatic. There’s always room in the lineup for God.