Back in April, Joe Maddon had the recipe for what would turn Javier Baez from an exciting-but-flawed player into one of the game's true superstars.
"I've talked about this for a bit where the moment he starts laying off the down-and-away slider, he's Manny Ramirez," said the Cubs' skipper. "He's got that kind of abilities at the plate. It's just a matter of maturing as a hitter, which he will."
Baez might not be Ramirez just yet, but he's undeniably having the breakout season we all were waiting for. After parts of four seasons marked more by his unofficial status as "baseball's most exciting player" than by actual production (he entered 2018 with a below-average career 90 OPS+), he is hitting .296/.330/.581 so far this year, good for a 132 OPS+. Baez has already set a career high for home runs with 25, and he's squarely in the mix in the National League Most Valuable Player Award discussion.
Baez is also not doing anything that Maddon suggested. Baez has long been described as a "free swinger," but his 2018 success isn't fueled by fewer swings; he's swinging more. He's not chasing less; he's chasing more. He's not laying off those bad sliders, either; he's going after them -- wait for it -- more.
Baez hasn't made any of the plate discipline changes you'd have expected if you were told that he'd finally be putting up the impressive production to match his prodigious skills. So, how in the world is he doing this? And perhaps more importantly for the Cubs, can Baez keep it up? Let's find out.

In order to understand where Baez is, it's important to understand how he got here. As a rookie in 2014, he struck out 41.5 percent of the time. That was the highest in baseball that year, because it was the highest mark in the history of baseball. (Seriously. There have been nearly 27,500 seasons of at least 200 plate appearances since 1901, and no one before or since had struck out so often.) In a world where we're hearing increasing chatter about how pitchers can't hit, all Major League pitchers this year are striking out ... 41.7 percent of the time. That's where Baez was as a rookie.
After a 2015 spent mostly in the Minors, Baez cut those strikeout numbers down to 24 percent in '16 and 28 percent in '17, then down to 23 percent this year, which is a tremendous improvement. Of the 178 hitters with 300 plate appearances in both '17 and '18, that's one of the 15 largest drops, and that's an impressive step forward.
At the same time, Baez has added a tremendous amount of power. He's added 101 points of slugging (from .480 to .581), a huge jump that's topped by only seven others, mostly guys having monster years like Mookie Betts and Matt Carpenter. Baez's hard-hit rate -- the percentage of balls hit at an exit velocity of 95 MPH or higher -- has also skyrocketed, from 35 percent to 46 percent, and that jump is seventh among those with 100 batted balls in both years.
That part is simple enough -- Baez is making more contact, and he's making more hard contact, and both of those are very, very good things.

But what's odd, as we noted above, is that Baez is not swinging less, he's swinging more, and he's finding himself coming up on some some historic leaderboards, at least back to 2008, when reliable pitch tracking data came online, encompassing over 1,600 player seasons.
He's swinging more
61 percent, up from 56 percent. It's the highest on record.
He's swinging more outside the zone
47 percent, up from 45 percent. It's the second highest on record.
He's swinging more inside the zone, too
78 percent, up from 71 percent. It's the 14th highest on record.
How about on sliders, like Maddon referenced? Baez is swinging at them more than ever, and he's swinging at them outside the zone more than ever. Curveballs? He's swinging the most at them, too, by an enormous amount. Baez is just swinging, constantly, all the time, always. It shouldn't work, but it is -- so far, anyway.

But there's one more thing Baez is doing more than anyone else, and this might help us tell his story. There's some signs he's focusing his aggressive approach.
In 2015, Baez went after the first pitch 28 percent of the time. In '16, that was 27 percent; in '17, it was 34 percent. That's all relatively steady and consistent. In '18, that's jumped all the way to 51 percent. It is, like everything else, the highest mark in baseball, and he hits .358/.373/.741 on the first pitch (though that's a little misleading, since you can't strike out on 0-0). If there's a word to describe Baez's '18, it might be: most.
Speaking of which, the flip side of all this is that Baez is still not walking, to an extreme. Even in the midst of his very good season, he went a stretch of six weeks and 37 games, from April 12 to May 30, without a walk. It's one of the longest streaks of the past 10 seasons.

Baez has 25 homers and 18 walks, which works out to 1.4 home runs for every walk. In the history of baseball, among players with 25 homers in a season, that's a rate that's been met only 20 times. It's not that you can't have a good season that way -- the 19 other players include MVP Award-winning seasons from Andre Dawson in 1987 and Ivan Rodriguez in '99 -- but it doesn't leave you much to fall back upon if the hits stop falling in, or over the fence.
In fact, let's push that one a little deeper, just to show you how rare this is. Baez is walking less than four percent of the time (3.8 percent) while still putting up outstanding offensive performance (136 wRC+, where 100 is "average."). Dating back to 1920, only three other qualified players have done the same thing: Carl Reynolds in '30, Felipe Alou in '66, Kirby Puckett in '88.
If those few and relatively random names don't make you feel strong about how sustainable this is, well, it's not really supposed to. While his value to the Cubs is about a lot more than just hitting -- Baez is an excellent and versatile defender and baserunner -- he is succeeding in a way that's relatively unprecedented, which tells you a lot about how difficult it is to maintain. It's not that it can't be done. It's just that it almost never has been before. Like everything else with Baez, his 2018 is an example of extremes.