There's been some chatter early on the season that Starlin Castro should change positions. With every error, the boo birds come out and talk ramps up about how Castro doesn't belong at SS. The claim is that he costs the team runs and ultimately wins.
The problem with that claim is that it's as inaccurate as a few of Castro's throws have been this year.
And I don't mean inaccurate in the sense that you can live with Starlin Castro's defense at SS because of his great offense at a premium position, though that part is true.
I'm saying it's wrong to say that Castro has been a liability on defense this year. Period. In fact, Castro has been an average to slightly above average SS so far this season. I'll get back to that in a bit.
If you focus solely on errors, you miss the bigger picture. Yes, he will make errors from time to time. Most 22 year old shortstops do. He needs to improve his footwork. He has worked hard at it but still gets sloppy at times on routine plays. It takes time to re-learn mechanics. He will get better once the new approach/footwork he has been taught this offseason become natural and not mechanical. At some point, it's going to click and he won't think about proper footwork. He'll simply do it.
But until then, his range, hands, and arm strength more than makes up for his occasional errors. Here's what I mean...
Thus far Castro's RZR is at .886. What's RZR? It stands for Revised Zone Rating and it measures, “the proportion of balls hit into a fielder’s zone that he successfully converted into an out”. That is what you ultimately want your SS to do.
Let me put that RZR into context. An above average RZR is about .860. A great one is about .900, so we can say that Castro's range by this measurement is very good. But that explanation doesn't do Castro justice. To understand how good that is and how much improvement he's made in this area early on, no regular SS last season had an RZR that high. Not Elvis Andrus. Not Troy Tulowitzki. Not Jimmy Rollins. Not Jose Reyes. None of them.
I'm not saying Castro has better range than those players or will sustain that RZR over a full season. It is a small sample size, but it's an improvement as far as Castro's individual play so far this year. His defense this season is what's being questioned, but to this point the numbers indicate that he his defense hasn't hurt the team overall -- and it may even be helping them. Castro's range runs (RngR) of 3.2 more than offsets his error runs (ErrR) of -2.3. In other words, his good range this season has been worth more runs than his errors have cost.
His UZR (Ultimate Zone Rating), which takes all defensive aspects into account, including errors, is a positive 0.1 this year. For all intents and purposes that is an average SS, but project that to 150 games (UZR/150) and Castro's rating is 5.5, which would make him an above average defender. In fact, that rating would have ranked 9th last year among shortstops with more than 1000 innings.
Intuitively, we all know that great range can make up for a few more errors. To put it in an oversimplified way, you'd rather have a SS that makes 10 more errors but gets to 100 more balls. That's a net gain in outs of 90 over the course of a season. It makes sense that you'd want a SS that creates as many outs (and thus saves runs) as possible on defense. RZR and UZR/150 are just more sophisticated ways of measuring that basic premise.
So, although the throwing errors may cloud things up a bit, it does appear that Starlin Castro is making progress. Advanced defensive metrics indicate that not only has Castro improved substantially over last season in terms of range, but he is actually playing a very solid SS overall over the first 21 games this season -- errors included.
Castro's offense is already a big bonus at what is considered a premium defensive position, but if he can continue to play solid to good defense while cutting down on his errors, he can become an elite player in this league.
Filed under: Analysis