During the off-season, I argued that while not earth-shakingly good, the Rockies’ catchers were fine, and in some categories in the top third of the league. With this in mind, I decided to see what Statcast had to offer in terms of catching to evaluate where the Rockies’ catchers are as compared to the rest of the league. What I found surprised me, namely that Chris Iannetta and Tony Wolters are remarkably similar when it comes to rating their pitch framing ability — and neither are particularly elite. That said, Tony Wolters has one of the best pop rates in baseball.
According to Baseball Savant, “Catcher framing is the art of a catcher receiving a pitch in a way that makes it more likely for an umpire to call it a strike.”
Baseball Savant tries to refine the measurement of framing in a couple of ways. First, it creates eight “zones” based on the catcher’s view around the strike zone as shown below:
Statcast then uses these zones to calculate “the called strike percentage of all non-swings in that zone.” The cumulative total of all non-swing strikes in all zones is the strike rate. Strikes are then converted to runs saved (Runs From Extra Strikes) “on a .125 run/strike basis, and includes park and pitcher adjustments,” so Baseball Savant takes park factors into account.
Baseball Savant even provides a sample sentence laying out how to articulate this data: “In 2018, Jeff Mathis converted 55 percent of non-swing pitches into called strikes in the Shadow Zone, the best rate of any catcher in baseball.”
Here’s a more concrete illustration. As of June 12, this is how Baseball Savant evaluates the top five catchers in baseball:
John Ryan Murphy has converted 54.9% of non-swing pitches into called strikes, currently the highest percentage in baseball. Austin Hedges, however, has by far the most runs from extra strikes — more even than JT Realmuto. Most non-called strikes are framed in Zones 14, 16, and 18, with Realmuto being significantly more effective in Zone 14 while Kelly Carson is the best at framing in Zone 16. Murphy, however, has the highest cumulative score.
Also, note how difficult it is for catchers to frame in Zones 11, 13, and 19. So this metric allows for a more nuanced evaluation of a catcher’s work.
With this in mind, I wanted to see how the Rockies’ catchers compared.
As measured by Bsseball Savant, neither Iannetta nor Wolters is particularly effective at generating strikes. Surprisingly, Iannetta is slightly better — and the two are listed consecutively, which suggests that their skills are, overall, roughly equal. Iannetta is significantly more effective in Zone 14, where Iannetta is almost as good as Realmuto, while Wolters is better in Zone 16. Frankly, I expected Wolters to be significantly better in all zones, but Baseball Savant indicates that is not the case.
After looking at framing, I turned my attention to pop time. Here’s how Baseball Savant defines this metric:
Pop Time measures the time from the moment the pitch hits the catcher’s mitt to the moment the ball reaches the fielder’s projected receiving point at the center of the base. Pop Time is a combination of exchange time (how quickly the catcher releases the ball, measured in seconds) and arm strength (velocity of throw, in MPH). Arm strength is measured on “max effort” throws, or the average above a player’s 90th percentile performance.
According to Baseball Savant, the average pop time is 2.01 seconds when a runner attempts to steal second. The average pop time to second base is 1.6 seconds to 2.5 seconds: to steal third base is 1.2 seconds to 2.5 seconds. The average exchange time is .4 seconds to 1.3 seconds.
As of June 12, here’s how top 10 MLB catchers ranked in terms of pop time:
Notice that in terms of pop time, Tony Wolters is ranked 8. (#DontDashOnTheStache, indeed.) That said, JT Realmuto is significantly better than all other MLB catchers. Chris Iannetta ranks 43rd with a pop time of 2.03.
Thus far in 2019, according to Baseball Reference, Wolters has thrown out 10 baserunners for a CS% of 40%. (For comparison, in 2018, he threw out 11 runners for a CS% of 27%.) Iannetta has thrown out 2 runners in 2019 for a CS% of 15%, which suggests that Iannetta just isn’t a quick as he once was.
So while the Rockies catchers are fairly equal in terms of framing, when it comes to pop time, Wolters marks a significant improvement over Iannetta.
What does it all mean?
In examining this StatCast data, I learned a few things. First, don’t try to steal on Tony Wolters. Just don’t. (Although really don’t try to steal on JT Realmuto.) When it comes to pop time, he is really that good.
Second, I assumed that Wolters is an elite pitch framer. Nothing in these data indicates that’s the case. It does suggest, however, that Iannetta and Wolters are remarkably similar, and they may be what Bud Black wants in a catcher. That’s probably tied to those “intangibles” I wrote about in the off-season — the ability of a catcher to work with a pitcher and a manager — none of which is present in in framing and pop time.
An interesting question going forward is what the Rockies will do at catcher in 2020. (I know: Finish 2019 first.) Iannetta’s contract ends, so the Rockies will be in the market for a new catcher to work with Wolters. Will they sign someone or bring in Dom Nuñez or Drew Butera? And what does the future hold for Chris Iannetta?