clock menu more-arrow no yes

Filed under:

Fun with White Sox Catch Probability

New, 25 comments

Ken Harrelson's first rule of baseball

Peter Bourjos increases his Catch Probability
Peter Bourjos increases his Catch Probability
Rick Scuteri-USA TODAY Sports

A couple weekends ago, MLBAM released version 1.0 of Catch Probability, an advanced metric for outfield defense derived from Statcast data. You can read more about it here (and here and otherwise on Mitchel Lichtman's Twitter, if you really want to dive into the weeds) but, essentially, it divides batted balls hit into the air to the outfield into five buckets. These buckets represent the likelihood of an outfield catch being made based on "opportunity time" and "distance needed". Opportunity time starts when the ball is released by the pitcher. Distance needed is the shortest distance the outfielder needs to make catch. The buckets are labeled via a star ranking:

  • 5 Star: 0 - 25%
  • 4 Star: 26 - 50%,
  • 3 Star: 51 - 75%
  • 2 Star: 76 - 90%
  • 1 Star: 91 - 95%
As noted in the linked article, there will be improvements in later versions to account for missing elements like direction of the batted ball, the effect of outfield walls (including most notably the Green Monster) on catchability, weighting of type of damage an opportunity presents (e.g., a 5 star could be a bloop just over the infield that's ordinarily just a single or a line shot to a gap that's ordinarily extra bases), so on. The buckets also represent a range and it's a near certainty that, in a given season, some outfielders get more opportunities at the top end of the range (i.e., easier) than the lower. Also, it currently measures all outfielders against one another and center fielders are likely hurt by such a comparison. And it should be noted that number of opportunities certainly plays a large role in value - just ask 2016 Adam Eaton.

That's why this article is labeled "fun". Right now we've only got two years worth of data and there are some missing ingredients. All that said, converting batted balls in the air into outs is the primary place where an outfielder can add defensive value. If you're failing to catch the easy ones, that's bad. If you're not catching your fair share of lower probability ones, that's bad. So let's look at White Sox outfielders and get a sense of who does these things well.

Adam Eaton

While he's no longer with the team, his 2016 defensive season is a most remarkable one and Catch Probability gives us some more insight into it. The one sentence narrative about Eaton's defense is that he was a poor/unremarkable center fielder who, when switched to right field, became an elite defender. The defensive numbers we had suggested that was accurate based on production but with the massive caveat that production doesn't necessarily track true talent. Catch Probability now at least suggests that those center field defensive numbers were misleading.

Let's start by going backwards. In 2016, there was no question that Eaton, playing mostly right field, was superb. He was rated at 18.0 Defensive Runs Above Average (DEF), which includes a position adjustment. He had a MLB-leading 22.5 UZR, of which 9.1 accounted for his range. He had 22 Defensive Runs Saved (DRS), trailing only Mookie Betts.

And Catch Probability backs those up. He caught 28.7% of 5 star opportunities, 57.1% of 4 star, 78.9% of 3 star, 86.7% of 2 star and 95.4% of 1 star. Most notable for his overall value, compared to other outfielders, he had the highest quantity of 5 and 4 star chances -- 72 in total. So the ball was finding him, which is not something he had control over. But he converted 30 of them, which is something he did.

Now let's take a look at 2015. Playing solely center field, Eaton was at -8.8 DEF. His UZR was -10.2, of which -6.8 accounts for his range. He had -14 DRS. Even accounting for the change in position, this wide of a differential doesn't really make sense.

And Catch Probability doesn't help us make much sense of it either. Eaton certainly didn't come anywhere close to his 2016 5 star catches as he caught a comparatively paltry12.5%. And his 4 star at 47.6% also trailed. But those don't seem like objectively bad percentages. 12.5% is right in the middle of the range for 5 star opportunities. And 47.6% is at the top end of the range. He also looks fine in the other buckets: 80.8% for 3 star, 88.9% for 2 star and 98.2% for 1 star.

We can theorize on some of the items I mentioned in the intro that aren't yet factored in. Perhaps in 2015, Eaton had a higher percentage of opportunities at the top end of the star buckets, particularly the 5 star, so he "really" should've caught those at a much higher percentage. But it is interesting to see that guys like Carlos GomezMichael Taylor and Austin Jackson whose Catch Probability profiles were similar to Eaton's found themselves more highly rated by the range factor in UZR. Will this perhaps be a situation where we find UZR didn't properly rate Eaton in 2015 (as the Nationals are certainly counting on)?

The rest of last year's outfielders

Well, they did about as well as you'd expect in Catch Probability.

Over the past two seasons, Avisail Garcia managed to convert 1 of 39 5 Star opportunities. Melky Cabrera converted 1 of 54. More problematic for Cabrera, however, is that he converted just 62 of 69 1 Star opportunities. Defenders of Cabrera have sometimes argued that he at least, unlike Dayan Viciedo, makes the easy plays. That doesn't appear to be the case.

J.B. Shuck is as horseshit as you'd expect. In 2016, 0% of 5 star and 4 star opportunities, 66.7% of 3, 87.5% of 2 and 84.6%(!) of 1 star.

Austin Jackson's season-ending injury is often cited as one of the main ingredients for the spectacularity of the White Sox collapse. Jackson, so the story goes, was playing a decent or better center and it paved the way for Shuck and Avi to get more playing time instead and eventually resulted in Eaton moving back to center. While defensive metrics weren't all that impressed with the Jackson part of the argument -- UZR/150 had him at -12.8 runs with below average range -- Catch Probability suggests that there may have been a bit more substance to it. While he wasn't making the spectacular plays -- he converted just 1 of 19 5 star opportunities -- he was doing a fairly good job with the rest: 45.5% 4 star, 50.0% 3 star, 91.7% 2 star and 100% 1 star.

A potentially surprising one, though, is Jason Coats. While he was given very limited time in the outfield - just 102 innings - he converted all six opportunities. That doesn't sound impressive until you hear that two of those were 5 star and one was 4 star (you likely remember one of them, when he robbed Miguel Cabrera of extra bases and collided with Shuck in his MLB debut). It's also interesting to see how those opportunities were apparently rated by Fangraphs' Inside Edge Fielding, which said Coats didn't convert any plays below their 60-90% bucket. While one might expect some margin of error in classification, it certainly calls into question what Inside Edge was doing if Statcast says two converted opportunities are 0-25% likelihood while they're saying there were much, much higher probability plays.

2017 roster contenders

Looking ahead to this season, Peter Bourjos has both found himself with an opportunity to make the team and is taking advantage of it. The other day, Jim asserted that Bourjos' defense isn't what it used to be and, sure, that's probably the case for a 30 year old. His arm has certainly declined. But, according to most defensive stats, his range remains very good and Catch Probability backs that up. He converted opportunities at a very above average rate across the board, most notably 23.5% 5 star opportunities and 58.3% 4 star, comparing favorably to the likes of Kevin Pillar and Ender Inciarte. As noted, he doesn't even have the arm of Pillar anymore, but a decent trick for hiding an arm is not letting the ball drop in the first place.

Perhaps not surprisingly for a guy who spent his career playing third base until 2015, Cody Asche is a pretty bad left fielder. The past couple years, he didn't come close to converting what would seem to be his fair share of 4 and 5 star plays and, more disconcerting, Asche was at 57.1% 2 star and 84.0% 1 star. Since he doesn't really have a bat, there's a reason he's a solidly below replacement level player and shouldn't be anywhere near a major league roster.

In a very small sample size -- 13 opportunities over the past two seasons -- Leury Garcia appears to be competent or better at catching balls. The fact that he's out of options, can decently play multiple positions and has good and useable speed may well provide him with a path to the opening day roster. But that won't really matter long-term if he can't improve upon his career slash line of .188/.225/.237.

The full Catch Probability Leaderboard is here.