Statcast recently released a version of their “outs above average” (OAA) defensive metric for infielders. Previously, OAA was limited to outfielders, but now it's available for infielders, too. For more information on how the metric is calculated, you should read Mike Petriello's excellent article at MLB.com. Of course, if you're a Cubs fan, you may have already heard about this new metric, as it says that Javier Báez is the best defensive infielder in baseball. Báez has always rated positively by advanced defensive metrics, but this is the first that has placed him so highly. If you're interested in more details about what makes Báez so good according to OAA, David Adler has a good deep dive, again at MLB.com.
If you just look at the year-by-year numbers, Báez’ 2019 seems like an inexplicable outlier. In 2017, he was worth 5 OAA, then only 1 in 2018, before increasing all the way to 19 in 2019. Upon closer inspection, a pattern emerges: Báez hasn't gotten better at making difficult plays, but he got much better at making more routine plays. The table below shows how many outs above average he garnered on plays that were less than 50% likely to be made, compared to plays that were easier to make:
|Year||< 50%||> 50%|
The numbers show that Báez made a huge improvement this year in terms of defensive consistency, a fact that I feel is backed up by the eye test.
On the other side of second base, Addison Russell‘s defense has declined over the past three years according to OAA. By normalizing his OAA totals to a 300-attempt (fielding chance) basis, we can see that he's declined each year, which also fits the general perception.
A divisive defender, David Bote was worth 3 OAA in 2019, but goes down to 0 when looking at plays with a > 50% chance. This makes sense when you remember the odd errors Bote made last year on what seemed like routine plays, despite his ability to make difficult ones. Bote was worth 5 OAA in 2018, though, so it's possible something weird was going on with him last year.
Kris Bryant has gone from 4 OAA in the infield 2017, to -4 in 2018, back to 2 in 2019. I would be curious to know how much his injuries over the past two seasons affected his defensive metrics, but going month-by-month doesn't reveal a stark pattern. Bryant is one player whose numbers here don't make a lot of sense to me.
The main everyday infielder that infield outs above average looks down on is, perhaps surprisingly, Anthony Rizzo, who has gone from 3 OAA in 2017, to 1 OAA in 2018, to -3 OAA in 2019. This goes against most fans’ view of Rizzo's defense, but another advanced defensive metric, Defensive Runs Saved (DRS) sees a similar decline over the last three seasons. In Rizzo's defense, OAA doesn't yet include “scoops” on low throws from infielders (although analysts generally feel the importance of that skill is overstated). Rizzo may also suffer if pitchers didn't cover first base on plays where he touched the ball first, but generally it makes sense that a first baseman with a recurring back injury would decline slightly as he ages.
Finally, Daniel Descalso was -4 OAA in 2019, and in a small sample, Nico Hoerner rated average at 0 OAA. Oh, and if you're interested, Nolan Arenado is the second best defender in baseball in this metric–a left side of Arenado and Báez would be by far the best in baseball according to Statcast.
Here's hoping there will be more Cubs news next week–until then, we must let thoughts of Bryant patrolling center field at Wrigley tide us over.