Where did this version of Austin Riley come from?

Regardless of what the perception of the National League East might be, the fact that Atlanta’s ballclub is currently leading it has to be considered something of a minor miracle. Having lost Ronald Acuña, Jr. to a torn ACL, Marcell Ozuna to legal issues, and Mike Soroka to a re-tear of his Achilles, it was not until August that the team had even posted a winning record. Yet, here they are. It’s only 1.5 games up on the Philadelphia Phillies (and the New York Mets aren’t too far behind, on paper), but a lead is a lead. At this point in the year, with the season they’ve had, it’s really kind of shocking.

Not nearly so much as the emergence of their third baseman, though. Sure, Atlanta could survive without Acuña and Soroka. They’ve got enough offensive firepower through the likes of Freddie Freeman or Ozzie Albies, and added enough pitching depth last winter, to at least remain afloat. Their movement at this season’s trade deadline helped as well. But it’s the emergence of Austin Riley that has been absolutely fascinating.

There had been a lot of talk over the past couple of years as to how the team could bolster what was already a pretty potent offense. Much of that discussion centered around Kris Bryant, with Atlanta appearing to be a primary suitor for him when the Chicago Cubs were very publicly shopping around his services. That buzz also had as much to do with the quality of player that Bryant is against the types of struggles that Riley had experienced over the course of the last couple of years.

The 2021 season represents Riley’s third “full” season at the Major League level. His rookie campaign in 2019 saw him record 297 plate appearances across 80 games. Therein, he slashed .226/.279/.471/.750; obviously that isn’t terribly inspiring, but it’s the power bat that caught people’s attention. His ISO came in at .245 as he hit 18 home runs and was barreling up pitches at a 13.7 percent rate. His hard contact rate came in at over 42 percent this year, which still stands as his highest rate to this point in his short career.

For Riley, though, the big issue was the lack of contact. He was chasing at a rate of 37.7 percent, had a SwStr% of 20.5, and made contact just barely 63 percent of the time. Ultimately, he struck out at almost a 37 percent clip. So it’s no wonder his wRC+ was still just 85 for the year, despite that impressive power in the small sample.

Speaking of small samples, Riley actually did show marked improvement in a number of regards in his 51 games in 2020. The strikeout rate fell to 23.8 percent, the contact rate was up at about 72 percent, and he cut the whiffs down to about 15 percent. This helped to lead to a notable uptick in average (.239) and on-base percentage (.301). Yet, perhaps unsurprisingly given the numbers themselves, he continued to sit as a below-average player by way of wRC+ (88), even with those modest improvements. A large part of that is the fact that while he made those improvements as far as contact and strikeouts are concerned, that came at the expense of his power. His ISO was just .178 and his Hard% fell about nine points. There was a massive jump in groundball contact, from about 26 percent in 2019 to over 41 percent in 2020.

So the first two seasons, albeit neither coming in a genuinely full campaign, showed kind of two halves of a really good player. You’ve got the power side and then that later-developed sense of the strike zone. The 2021 season is showcasing exactly the type of player that can manifest when you combine those two sides of the coin.

Having come in with two seasons under the replacement level threshold, Riley is at an fWAR of 3.7 for the season, third on the team, trailing only Acuña’s 4.3 and Albies’ 3.8 (side note: Can we talk about how absurd it is that Ronald Acuña, Jr.’s fWAR is that high despite not having played a game since July 10th? Just speaks to the kind of year he was having). That figure leads all National League third basemen (and trails three AL 3B’s; you can probably name them off the top of your head). For Riley, this isn’t a matter of a guy simply on a hot streak (as we’ve actually seen Riley do in two short years) or establishing a new element of his skill set. This is a mental side that’s far more difficult to quantify.

The Athletic’s Keith Law (paid subscription) has a great writeup on what some of those mental changes entailed. As easy as it might be for us normies to think it might be to figure out the strike zone and improve pitch recognition—or at the very least think of it as a sort of black and white concept—it is very much not that. Rather than regurgitate what Law features in his article, we’ll simply look at the outputs that have resulted from Riley's reevaluation of pitch selection and the zone itself.

Riley’s K% is the exact same as it was last year (as of this writing), at 23.8 percent. That’s hardly a number to scoff at. Especially when the walk rate is up (9.1 percent), the whiffs are down (12.4 percent), and he’s making contact at a higher-than-ever rate (74.7 percent). More importantly is that while he’s demonstrated improvement there, the power has also returned. His ISO is at .233, with 29 homers thus far. It all culminates in an absolutely eye-popping slash of .305/.377/.538/.915 and a wRC+ of 141.

What’s really cool about Riley’s breakout is that he isn’t necessarily swinging less. Well, he is swinging less (49.1 Swing% is about five off of last year), but that’s a not general explanation as to how he’s finding the level of success that he is. Against breaking and offspeed pitches, he’s dropped his swing rate by barely a single percentage point. Yet, he’s managed to cut his whiff rate against those pitches in extremely significant fashion, including an 11 percent decrease in Whiff% against offspeed pitches. It’s all about pitch recognition here, and it’s making all the difference. He’s taking those tools and now building on them.

And, really, the 3.7 fWAR mark is kind of another minor miracle when you consider that he ranks among the league’s worst fielders, regardless of position. But we’re not here to litigate that—or Riley’s potential MVP candidacy, for that matter. Riley’s breakout is fun regardless and really speaks to that mental side of the game that we don’t always get to see transpire. In this case, the results just so happen to speak for themselves.

Randy Holt is a contributing writer for Beyond the Box Score.