Last week, with baseball’s attention firmly fixed on the fall out from the Astros’ sign-stealing scandal, the Twins signed Josh Donaldson to a long-term deal. You’d be forgiven if the signing slipped your mind; there was a lot going on. The Braves, however, are certainly aware that Donaldson is no longer a member of their organization; I’m sure the Nationals (and really, the rest of the NL East) are at least happy to have him out of their division. There’s no denying Donaldson’s impact in 2019 — a 132 wRC+ over 659 PA and 4.9 WAR in 155 games made him one of the best free agent signings of last offseason. And while the Nationals ultimately won the World Series, there’s a more-than-reasonable argument to be made that Donaldson represented the difference in the Braves winning the division crown.

Without Donaldson in the fold, the Braves’ lineup is due to take a step back. Of course, this is still a team flooded with talent; among the six position players to amass at least 400 PA for Atlanta last year, five had a wRC+ above 100. Their offensive output was led by Freddie Freeman (138 wRC+) and certainly more than aided by Ronald Acuña Jr. (126) and Ozzie Albies (117). That trio will be back this year and supplemented by outfielder Marcell Ozuna (110), signed last night, and catcher Travis d’Arnaud, who represents something of a wild card offensively, though he did post a 107 wRC+ during his time in Tampa Bay. But perhaps the Braves’ solution to soften the offensive blow of Donaldson’s departure is the player who spent all of last season next to him in the field: Dansby Swanson.

To date, Swanson has pretty much spent his entire major league career operating under the light-hitting, good-defense profile that is more indicative of shortstops in the earlier portion of the previous decade:

Shortstops posted a 98 wRC+ last season, the best they’ve hit in 115 years, since they posted a 101 mark in 1904. Simply put, at no other point in the league’s last 100 years were shortstops expected to be as good at hitting as they are now, so Swanson’s numbers generally pale in comparison despite being solid overall. He posted a career-high 92 wRC+ last year on the back of a .251/.325/.422 line. But what you don’t see in those numbers is the potential for much better offensive production in 2020. Swanson was actually one of the league’s most improved hitters over the last calendar year, and I’d argue there’s a good chance that 2020 could be Swanson’s first full season during which he’s above-average with the bat.

A lot went right for Swanson last season, but much of that success remained below the surface. One measure of Swanson’s improvements is his xwOBA. From 2018 to 2019, Swanson’s xwOBA jumped by 69 points, the sixth-highest year-over-year increase among hitters with at least 200 batted ball events. His .347 xwOBA put him in the 69th percentile overall. As you’d expect, Swanson behaved like a breakout hitter — he hit the ball harder and with more loft. But while he did improve, his offensive numbers were far from eye-popping.

First, let’s dive a bit deeper into Swanson’s development in 2019. He posted a career-high line drive rate, a career-low groundball rate, and continued to spray the ball all over the field. For a player whose game is centered around contact and speed — Swanson has 88th-percentile sprint speed — these appear to be the ingredients necessary to making steady progress.

Swanson was a menace to fastballs last year, posting a .368 wOBA (think Matt Olson-esque) and .386 xwOBA (think J.D. Martinez-esque) against them. He also made steady improvements against non-fastballs, though none of his stats — expected or otherwise — would suggest he’ll be an above-average hitter against the soft stuff next year.

Much of these breakthroughs start with discipline. Swanson’s strikeout and walk numbers didn’t shift much from year to year — he added a point to his walk rate and lost a tenth of a point of strikeout rate — but where he really improved was getting himself in fastball counts. Of the 2,223 pitches Swanson saw last year, 29.1% of them came while he was ahead in the count, a career-high, landing him in the 72nd percentile league-wide. Of course, getting ahead in the count doesn’t guarantee success, though there is a moderate correlation (r = 0.41) between the percent of pitches a hitter sees ahead in the count and their seasonal wRC+.

Swanson became choosier at the plate, swinging at just 45.8% of pitches overall, while also opting to only swing at pitches he can drive. He’s always done the most damage against fastballs, but prior to last year, his eyes appeared to light up at all fastballs, not just the ones in his wheelhouse. He swung at 18.4% of fastballs in the chase and waste zones in 2018, but he dropped that number all the way to 12.0% in 2019.

Here’s a 2-0 fastball Swanson had no business offering at from 2018:

If Swanson takes that pitch, he would have gotten to 3-0, a count that saw hitters post a .551 wOBA and a 256 wRC+ in 2018. Instead, he found himself 2-1, a count that offered much less favorable (though still good) split in comparison (a .358 wOBA and a 126 wRC+). Of these poor swings in 2018, 63% came while Swanson was either ahead or even in the count. There were 34 different occasions in 2018 where he could have run completely different splits just by laying off a bad fastball. And, as Ben Clemens chronicled earlier this month, the count is always king. So Swanson really did two things here: he reduced his swing percentage on bad fastballs overall, and he was seemingly more cognizant of the count when doing so. His O-Swing% on fastballs when behind in the count was just 27% last year, compared to 35% in 2018.

We know Swanson likes to swing at fastballs, given that he does the most damage there, but if we expand this analysis to all pitches, we see the theory hold up. Swanson swung at 32% of all pitches outside the zone while behind in the count in 2018, and he reduced that figure to a career-best 29% in 2019. He’s far from elite at this skill — Mike Trout, for example, only swung at 20% of pitches outside the zone while ahead in the count — but being in the 70th percentile isn’t bad at all.

Thus, the development becomes coherent. Swanson improved his underlying discipline, put himself in more favorable counts, and made pitchers throw fastballs. Then, upon receiving those fastballs, Swanson crushed them, putting up elite xwOBA figures against them. That, combined with making his performance against other pitches less bad, led to a breakout year.

Except it didn’t. The definition of a breakout is up to interpretation, but Swanson was still a below-average hitter last season. He experienced something of a rare case — he did nearly everything right, but was bitten by the bad luck bug, which masked those underlying areas of growth. On 43 different occasions last season, Swanson had a batted ball with a .500-plus xwOBA turn into an out — among the 142 hitters with at least 100 batted balls with an xwOBA of at least .500, Swanson’s 33.3% “crushed-but-out” rate ranked as the 12th-highest in baseball.

Swanson was robbed of both contact and power last year. He hit .337 on contact (effectively BABIP while including homers) last year, 28 points below his .365 expected batting average on contact. Meanwhile, his xISO (xSLG-xBA) was .209, 37 points above his actual ISO of .172. By no means would Swanson have been one of baseball’s best hitters last year, but a .271/.343/.480 line using his expected statistics looks a whole lot better than his actual .251/.325/.422 line.

Will Swanson become the next Josh Donaldson? Probably not. But there is the potential for much more from the former No. 1 overall pick. While xwOBA is park-neutral, and is therefore absolved of park factors, I estimated what Swanson’s rough wRC+ should have been had he produced at the level that his xwOBA suggested. It comes out to 112, which would not only have made him one of the better hitters on the Braves, but also in the top third of shortstops league-wide.

We’re already well aware of Swanson’s defensive capabilities. If he hits like I expect him to in 2020, the Braves might just have another 3-4 WAR player on the roster. In 2019, that potential was simply disguised by some unfortunate luck.