Javy Baez, from Curveball Victim to Baseball’s Best Curveball Masher

Javier Baez probably didn’t do enough this season to actually win the National League MVP award, but that’s due more to Christian Yelich’s Barry Bonds explosion in the second half than any shortcomings on Baez’s part. I mean, check out this slash line: .290/.326/.554; 34 homers, 111 RBI (131 wRC+). Dude was fan-freaking-tastic at the plate.

And perhaps more importantly, his progress this season qualifies as that huge leap forward at the plate for which we all hoped, but feared might never come. In addition to the increased power and solid batting average, Baez lowered his strikeout rate down to 25.9%. That is a PERFECTLY acceptable range for someone with his power numbers (.264 ISO, career best).

I think there are probably a lot of reasons Baez improved so dramatically this season, but there’s one thing, in particular, I’d like to focus on here: his improvements against the curveball.

Check out what @CubsProspects noted:

Javier Baez Vs Curveballs

Pre-2018
Swing%: 56.2
BIP%: 15.1
wCB: -10.7

2018
Swing%: 69.7
BIP%: 27.2
wCB: +12.0

Baseball’s best hitter against curveballs this season, per FG. Turned skill that was weakness into being the world’s best.

Incredible @javy23baez!

— Cubs Prospects (@cubprospects) October 12, 2018

From his debut in 2014 up through the 2017 season, Javy Baez’s -10.7 wCB (weighted curveball runs above average) ranked 9th worst in MLB. But this season, alone, Baez completely flipped the script. Not only was he no longer one of the worst curveball hitters in the game, he became *literally* baseball’s best – one spot ahead of Christian Yelich, as it turns out. But that wasn’t the only pitch he improved upon.

Take a look.

Weighted Runs Above Average/Pitch (’14-’17):

1. Fastball: +3.2
2. Slider: -1.9
3. Cutter: 0.3
4. Curveball: -10.7
5. Changeup: -4.3
6. Split-finger: 1.9

Weighted Runs Above Average/Pitch (’18):

1. Fastball: +17.5 (+14.3)
2. Slider: +2.8 (+4.7)
3. Cutter: -0.5 (-0.8)
4. Curveball: +12.0 (+22.7)
5. Changeup: +1.5 (+5.8)
6. Split-finger: -0.9 (-2.8)

Baez didn’t make sweeping improvements across the board, but clearly curveballs were not the only pitch he saw better in 2018. In addition to massive improvements on that pitch, he also started HAMMERING fastballs better than ever (25th best in MLB), and made a great deal of progress against sliders, too.

You do hate to see that the cutter is still giving him fits – something to work on! – but if he’s really made that much progress against the slider, which is often thrown low and away, off the plate, you’ll find me smiling widely and as optimistic about his offensive future as I’ve ever been. We’ve always known Baez has been capable of hitting fastballs, but this progress against offspeed and breaking stuff is very heartening.

Now, these weren’t the only improvements Baez has made – and he still has plenty of work to do (his out-of-zone swing rate this season was still sky-high, for one example) – but this is the sort of underlying data you LOVE to see when a guy breaks out, not only because of the context it provides, but also because of how acutely we *knew* breaking pitches were hurting him in the past.

The way I see it, that tweet lays out it out perfectly. Baez took something that was an Achilles-heal-level weakness – hitting curveballs – and became *the best* player at it this year. How’s that work for ya?