This is not going to be a long post. I’m tempted to post the one table in it without comment, but that wouldn’t be much of an “article.” If you’ve been paying any attention to the Braves for the last few years, you are probably aware of the Austin Riley saga:
- First six weeks of major league career, mid-May to June 2019: Riley debuts with a bang, sets or challenges all sorts of “first to X homers in Y PAs/games” records, and has a bunch of hits and dingers in key situations. Life is good.
- Rest of 2019: Riley’s offensive aptitude takes a complete about-face, to the extent that he totally tanks his season line.
- 2020: Riley does somewhat better, but underperforms his contact inputs such that on the surface, he’s still a below-average bat.
- First three-ish weeks of 2021: Riley is just terrible across the board; the hits he does garner tend to be almost accidental swinging bunts and the like.
- Rest of 2021, to date: Riley is a monster, a demigod, pitchers’ worst nightmare. Seriously, from April 18 through May 23, Riley had the best wRC+ in baseball (210) and with 1.9 fWAR in that span, tied with Nick Castellanos as the most productive player in MLB. (His 0-for-4 in Tuesday’s win over the Red Sox has dropped him to seventh in fWAR since the start of April 18.)
Or, in visual form, focusing on 2021...
While this rocketing rebound has indeed been aided by some outperformance of his peripherals (.402 wOBA, .365 xwOBA on the season), Riley’s xwOBA during the climb has been fantastic anyway at an even .400 and has been something akin to karmic justice for his 2020 underperformance — his career wOBA and xwOBA are now .331 and .332, respectively.
During Riley’s prior ups-and-downs, a lot has been made about the reasons for his struggles, given that his debut and the six-week stretch thereafter was a bombastic (and bombtastic) success. While anyone who says it was due to sliders should be bonked with a big foam mallet at this point, the story itself is fairly complicated in general. The table below is the reason for this post, and it kind of has everything, so you can really build your own story if you wish.
When Riley hit the ground running in May-June 2019, he feasted on slower fastballs (including sinkers) and curveballs. When the rug was pulled out from under him, he pretty much just got worse across the board, but what killed him was basically not being able to do anything with fastballs of any velocity. (For all of you wondering why you got hit with a foam mallet — a .375 to .210 xwOBA drop, with only a .021 drop in xwOBA on sliders when there are xwOBA drops of .200+ against other pitch types... yeah.)
2020 was an interesting two months for Riley: whatever the impetus (rightly or wrongly), he really did make huge gains against the slider, making him the oddball “hits breaking pitches relatively better than fastballs” guy. He improved against fastballs, too, but just not enough — if the league is hitting any pitch 90+ mph at a .349 xwOBA and you’re only managing .312, with the split being .322 to .207 at 95+ mph... that’s a tough place to be, even if you are a savant at dealing with breaking pitches.
Then, we enter the beginning of 2021, and everything falls apart again. Four-seamers were eating Riley up and his relative success against sinkers couldn’t make up for it, making him lag the league in performance against fastballs at any velocity. The gains against sliders from 2020 were completely gone, curveballs were still being hit but not quite at the rate as before, and weirdly, there was decent performance against changeups. Still, not an ideal situation by any means, given that it looked more like the latter part of 2019 than even 2020.
And then, everything changed. Since the start of April 18, Riley is killing fastballs of almost every velocity and type. For the first time in his career, he’s outperforming the league on 95+ mph fastballs, and he’s destroying the stuff that’s thrown a bit slower, including sinkers and cutters. Changeups are somehow being walloped too. The only thing that Riley has “given up” is some diminished performance on sliders as well as curveballs — the slider is the only pitch type he sees frequently where he’s still underperforming the league. But clearly, it hasn’t mattered, given his rampage through the league.
It remains to be seen what this portends for the future. Maybe this is just New Austin Riley, here to stay and purge the land of fastballs and changeups of all speeds and stripes. Maybe all that this has shown us is that Riley is going to be boom-and-bust, the way that we saw his struggle periods have terrible numbers for most velocities and pitch types.