Theorizing Edman’s Sophomore Slump

Over the last few seasons, St. Louis fans have been witness to one of the better middle-infield duos in the entire league. The dynamic of Paul DeJong and Kolten Wong has been a fun one to watch over the last few seasons, especially on the defensive side. They were certainly the most successful SS/2B combo the Cardinals have seen in quite some time, and during a short-lived era in which the team as a whole seemed to be treading water in the NL Central, they helped keep them afloat. In the four seasons between 2017 and 2020, they accumulated a collective +75 Defensive Runs Saved, +43.2 Ultimate Zone Rating, +16 Outs Above Average and +21.2 Wins Above Replacement (via FanGraphs). They were the sort of duo up the middle that you wanted to see stick around for several more years to come, but unfortunately that wasn’t meant to be. Instead, the front office found themselves at a crossroads; one path would lead them to pick up the 2021 option in Wong’s contract and pay $12.5M in the process, while the other path would save them $11.5M of that money (after a $1M buyout) and allow them to hand over the keys to second base to the younger, cheaper, controllable option: Tommy Edman.


So now that Edman is DeJong’s new parter-in-crime at second base for the time being—and quite possibly even the distant future—we should probably take a look into what kind of player Tommy has proven to be up to this point, and what kind of player we can expect him to be in the future. The latter isn’t always easy to do, but we’re going to try nonetheless.


The Defense:


Let’s start with the aspect of Edman’s game that has been the most consistent up to this point: his glove. While filling the shoes of a guy who is probably the best defensive second-baseman in MLB may be a daunting task, Tommy has proven to be quite the playmaker himself. He’s done it at multiple positions though, so we’ll be looking at his defensive numbers all over the diamond (except for center field, as he’s only played 1.0 inning there).


The following are Tommy Edman’s defensive numbers from 2019 and 2020 combined:

As you can see above, Edman has seen much of his defensive success come in right field—a position in which he didn’t play a single inning in the minor leagues—third base, and second base. While it’s unlikely that Edman gets many innings in the outfield in the upcoming season, it’s incredibly impressive to see a player so versatile that he’s seemingly above-average defensively no matter where you put him. It’s even more impressive that in such a limited time at second base, he’s put up numbers that are comparable to those that Kolten Wong put up in 2020, as I wrote about in more detail here. It’s also incredibly convenient, seeing as Edman is set to be Wong’s successor at the position.


So when it comes to second base, I don’t believe the Cardinals have anything to worry about on the defensive side of the ball. As for the offensive side, that’s where the question marks start to rise for Edman.


The Offense:


Let’s start with the obvious: Tommy Edman over-performed offensively in 2019, and was bound to regress.


During his time in the minor leagues, Edman averaged a modest 106 wRC+, which is to say that his bat was about 6% better than the average MiLB batter. When he burst onto the scene in his rookie year and posted a .304/.350/.500 slash-line and a 123 wRC+—or 23% above league-average—it came as quite the surprise. Of course, this was most likely not sustainable. After all, Edman out-performed his .286 xBA by 18 points, his .450 xSLG% by 50 points and his .337 xwOBA by 19 points. Still though, even if he regressed down to what he was expected to have produced, it would’ve made for a very solid offensive year. So yes, he was expected to regress, but perhaps not to the severity that he did in the shortened 2020 season.


In 2020, through 227 plate-appearances, Edman’s numbers fell to the tune of a .250/.317/.368 slash-line and a 90 wRC+. Those are significant drops in production, but perhaps not too far off from what was to be expected from his second year in the majors. In fairness to Tommy, that’s only 10% worse than league-average, so it wouldn’t be entirely off-base to suggest that if Edman had gotten the chance to play a full season, he could’ve eventually leveled his numbers out to a league-average clip.


But what do the “expected” stats have to say about his sophomore season? In his rookie season, they told a story of Edman out-performing his actual production by a decent amount, but in 2020 they told a somewhat different story: Edman actually got unlucky, if only just a little. His xBA was 15 points higher than his BA, his xwOBA was 8 points higher than his wOBA and his xSLG% was just 1 point lower than his SLG%. While losing 15 points on your batting average certainly doesn’t help matters, I also wouldn’t say that bad luck is to blame for his underwhelming offensive season. In order for that to be true, I would need to see a contrast between his SLG% and xSLG%, and it just isn't there. Tommy didn’t slug the ball even slightly, and the numbers reflect that.


So if bad luck isn’t to blame, what could be another reason for his sophomore slump? Well, it might have something do with Edman not swinging the bat. Seriously, he swung less at everything.


He swung less at the first pitch of an at-bat:

He swung less at pitches in the strikezone:

He swung way less at Meatballs (pitches right down the middle):

And he swung less at pitches overall:

Call me crazy, but I don’t believe he just forgot to swing at pitches right down the middle. Edman was clearly trying to do something different in 2020, and my theory is that he was taking more pitches in an attempt to drive his walk-rate up. If that is what he was going for, then it sort of worked. His BB% did go up from 4.6% to 7.0%, but that’s still below the league average of 8.3%.


Of course, a significant side effect of Tommy just deciding to swing less is that he was also swinging less at pitches he should have swung at, especially early in the count, which likely resulted in him getting behind in a lot of two-strike counts and eventually either striking out—which he did more in 2020 as well (an increase from 17.7% to 21.1%)—or getting out in other ways, like groundouts. This is also backed up by data, as Edman saw his Groundball% jump from 41.9% in 2019 to 51.3% in 2020. More than half of the time he made contact last year, it resulted in a groundball. Edman is a speedy guy, but it would be hard for even the fastest players in the league to produce offensively when more than half of their batted balls are likely to head straight to an infielder.


What To Expect:


The future, as it turns out, isn’t really an easy thing to predict. However, looking at the past is oftentimes a good place to start, so let’s do just that. What exactly do we know about Edman’s disappointing sophomore season?

  • We know that he swung at pitches less than he did in his rookie season, and less than the average MLB hitter.

  • We know that he swung far less at Meatballs than he did in his rookie season, and far less than the average MLB hitter.

  • We know that he hit the ball on the ground significantly more than he did in his rookie season, and far more than the average MLB hitter.

  • We know that he struck out much more than he did in his rookie season.

  • We know that his offensive statistics (both results-based stats and expected stats) took a significant plunge as compared to his rookie season numbers.

The only question now is whether we can prove that these abnormalities are mutually exclusive. Some of them are more clearly correlated, of course, like his drop in SLG% and his spike in Groundball%. Those two line up pretty well all on their own, seeing as it’s infinitely harder to get extra-base hits when you aren’t hitting line-drives or fly-balls.


As for others—such as connecting his low 1st Pitch Swing% to the increase in his Strikeout%—it’s a little harder to prove. I can’t determine that those two correspond with one another, because that is based on the assumption that the 1st pitches of an at-bat he decided not to swing at were strikes and not balls that he was correct to lay off. However, we know for sure that he swung significantly less at strikes down the middle and at strikes overall, so there is definitely some merit in attempting to align these two things. The point I’m making here is that I can’t definitively prove that if Edman swings more at strikes, meatballs or pitches overall, he’ll see his offensive production return to an above-average clip. However, there doesn’t appear to be many other working theories when it comes to Edman’s lackluster performance in 2020, and this one makes a lot of sense to me personally.


For the time being, all we have are numbers from two seasons in which the sample size for each is just too small to predict what Tommy Edman can be in a full MLB season. Once we have a larger sample size than 147 career games played, it’ll likely be easier to see if there is a continued correlation between him swinging more and being rewarded for doing so, or the opposite. Until then, we won’t really have a definitive answer to what kind of player Edman is, or what we can expect to see from him in the future. What we do have is a theory, and as with all theories, all we can do now is wait patiently for it to be accepted as fact, or to be proven wrong.

Credit to FanGraphs and BaseballSavant for all stats referenced in this piece

Credit to @veryonlinejoel for editing this piece

Credit to @cardinalsgifs for the cover art