No matter what kind of data is used to evaluate Taylor Walls, it’s clear that he is one of the best defensive shortstops in professional baseball. You don’t need the stats throughout this article to know this, either. The eye test and numbers both agree that he has been the best SS defender since he entered the league.
Maybe the biggest barrier to winning a Gold Glove has been an assortment of injuries throughout his career that have kept him from playing in fewer than 120 games in four of his six
professional seasons; however, Walls has logged over 1,000 innings at SS for the first time in a single season this year, and his defensive production is significantly better than the rest of the American League Gold Glove contenders at the position.
In his second consecutive year nominated as a short stop, the award should be his. Let’s break down why.
Defensive Runs Saved
One of the most important defensive metrics used to evaluate players is defensive runs saved (DRS). DRS assigns a probability of success to each play a defender attempts to make, and that value is subtracted from one to determine how many defensive runs are either added or subtracted from a player’s total DRS.
For example, if a batted ball has a 90% probability to be converted into an out by a SS and the player completes that play, they get +0.1 DRS added to their season total. However, if they fail to make that play and the runner reaches base, they would have 0.9 runs subtracted from their DRS total.
Right now, Walls leads all AL SS who have at least 750 innings at the position with 21 DRS. The next closest is Zach Neto with only 9 – and Walls has played roughly 300 fewer innings than him. DRS is a counting stat which can be flawed because a player with a higher volume of innings has an advantage. It can be more beneficial to look at DRS on a rate basis. It’s clear that, by DRS, Walls has been the best defensive SS in the league, and it’s not really close when looking at this year’s nominees:
Bobby Witt Jr. is the main contender for the AL SS Gold Glove with Walls, and his DRS per 1,000 innings is a much lower 6.6 compared to Walls at 20.3.
Outs Above Average
The other popular defensive metric is Outs Above Average (OAA). It essentially captures a defensive value for each play in a similar way to DRS, but it accounts for a few more factors: how far the fielder has to go to field the ball and how much time he has to get there based on the speed and location of the runner who put the ball in play.
It still works with similar probabilities and values that DRS uses, but an important distinction is that it doesn’t begin tracking the play until the pitch is released. This is different from DRS; DRS simply asks “what is the probability the defender makes this play, and did they make it?” while OAA captures fielder location and batted ball data beginning at pitch release.
Why does this matter? Walls is special because of his ability to read swings, understand a pitcher’s approach, and anticipate batted balls. If you’ve ever had the opportunity to watch him live and in-person, you’d notice he’s constantly adjusting and – most importantly – he’s in motion and proactive on batted balls. This means that OAA doesn’t accurately capture his starting position as Walls is already in motion and closer to a batted ball than another fielder would be.
Walls has the third fewest OAA among shortstops from the same group we looked at earlier with -3 OAA, so at surface level he looks like one of the worst defenders by this metric. However, there are a pair of components within OAA that still show us that Walls is the best defensive SS in the league.
One component of OAA is called “estimated success rate,” and this is simply the expected fielding success rate for a given player. Given that Walls gets into better starting positions than others because of his anticipatory skills, we would expect him to have a higher estimated success rate than most – and he does. His estimated success rate is 82% this season. The next closest in the AL is George Lombard Jr. at 79%, and the league average is around 75%. Witt’s estimated success rate is near the bottom of AL shortstops at 70%. This suggests Witt has some of the worst starting positions, but his plus-plus athleticism helps him make up for it.
The other OAA component that supports the idea that Walls is the AL’s top SS defender is the actual success rate. Walls once again leads the league with an 81% success rate with the next closest being Ezequiel Duran at 79% at Witt at just 75%. OAA is calculated using the difference between estimated and actual success rate across all plays and have a high volume of positive or negative OAA plays is where a total OAA value comes from. Witt is able to make up for his poor positioning by having a plus arm and strong reactions, and his difference between estimated and actual success rate is +5%.
While Walls is more proactive and on occasion might incorrectly anticipate a batted ball, so the difference between his rates is -1%. Still, I can’t imagine a single coach who would prefer a defender who makes 75% of plays compared to one who makes 81% of plays – giving Walls the edge over Witt once again.
Here’s how the AL Gold Glove nominees compare in estimated success rate, actual success rate, and total OAA:
Again, Walls has the advantage over both of the other nominees. He simply converts more batted balls into outs at a higher rate than any other shortstop defender. His total OAA isn’t able to account for his anticipatory skills, but we do see it reflected in his success rates. Total OAA unintentionally rewards players who have poor positioning, and it punishes those who are able to read the game and adjust before the next pitch is delivered. It’s apparent that looking at estimated and actual success rates in relation to OAA are more helpful for evaluating defense than simply looking at total OAA.
Here’s how all of the Gold Glove nominees compare in both the AL and NL. Walls is simply in his own tier even among the best defensive shortstops this season:
SABR Defensive Index
A potential barrier to Walls earning his first Gold Glove is the SABR Defensive Index (SDI).
SDI is an aggregate of a variety of defensive data, and it’s a counting stat — meaning players with more innings can add to their SDI total more easily than players with fewer innings. The SDI accounts for 25% of the Gold Glove selection process. The last public update is from August 9th when Witt had a slight edge over Walls at 8.4 versus 6.7. It’s possible that Walls caught or even surpassed Witt over the last six and a half weeks of the regular season despite playing in nearly 170 fewer innings, but we’ll have to wait a see when SABR releases their final update.
I wonder if SABR uses the SDI on a rate basis; it would be a more accurate measurement of a player’s true ability if they used it as a rate rather than counting stat. If we scale SDI to 1,000 innings, Walls has a 6.5 SDI per 1,000 innings, and Witt has 6.9. Advantage still goes to Witt here, but it’s much closer on a rate basis.
While Walls has been deserving of Gold Glove for a long time now, he finally has the workload to put him in contention. I’m not sure how much I trust the voters to make the correct decision, but the data makes it obvious: Taylor Walls was the best defensive shortstop in the American League this year.
