On Thursday, Statcast unveiled a new defensive metric: outs above average. Essentially, they use catch probability to determine the “expected” number of plays the average outfielder would have made given set of opportunities, and compare it to how many plays that given outfielder actually made. It’s really a pretty intuitive and simple concept.
Outs above average, or OAA, also appears to stabilize over a much shorter period than other defensive metrics like Range Runs in ultimate zone rating or rPM in defensive runs saved. Stabilizing over a shorter period makes it much more relevant to single season and in-season discussions.
The important thing, though, is that it gives us another way to evaluate the St. Louis Cardinals defense. At least, the outfield defense. And by OAA, through September 13th, the Cardinals rank 22nd at six outs below average.
But what does that mean? It’s hard to say. We don’t know the run value resulting from the outs gained or lost. Are the Cardinals letting a few more singles fall, or are they allowing additional extra base hits?
According to rPM and RngR, which focus on run value, St. Louis rates out slightly better at 20th and 15th, respectively. So outs above average is slightly more pessimistic about the St. Louis defense, but they’re all basically telling the same story. We’ve suspected all year that Cardinals have been playing below average defense in the outfield, and this is just another way to confirm that notion.
How do the individual players stack up? Here’s the leaderboard for St. Louis outfielders with at least 100 innings played.
Tommy Pham rates out as the Cardinals best outfielder by OAA in 2017. That’s probably not a surprise. If you’ve watched Dexter Fowler this season, it’s also not surprising that he brings up the rear. Among the 157 players who have gotten at least 50 opportunities in the outfield, Fowler’s 8 runs below average ranks 152nd. His defense, of course, has been under the microscope all season and rightfully so.
Additionally, we see that Jose Martinez rates out terribly over his 280 outfield innings thus far, while Harrison Bader has made a strong first impression. We don’t really know how reliable small sample size OAA numbers are yet, but this at least passes the eye test.
Perhaps of more importance are the changes from 2016 to 2017. Pham’s seven out improvement equates to more than twelve outs over 1,000 innings and is by far the best on the team. Given such rapid improvement, I’d argue that Pham’s vision issues impacted his defensive play last year. So, while the sexy benefit to his restored vision in 2017 is his 147 wRC+ and 20-20 campaign, his defensive improvement is more subtle. Yet, that defensive progress has made him a more complete all-around player and contributed to his team leading 5-WAR season.
Fowler, on the other hand, has dropped 9 outs from 2016 to 2017. How much his decline is due to playing his home games in an unfamiliar and bigger park, injury, positioning, or otherwise is hard to say. But Fowler has been terrible at the most important position in the outfield, and it’s costing his team.
Overall, outs above average is a great new tool to use when evaluating players’ defensive performance and skill. It’s very simple to understand, yet has the potential to lead to more insights than existing metrics. It’s certainly better to use for single season (or less) commentary and analysis. I’ve yet to play around with OAA as much as I’d like, but you can see a thread with my initial thoughts and some early calculations here. In the meantime, hopefully this was a useful high level overview.
Thanks for reading!