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Twins buy in to pitch framing with Jason Castro deal

The Twins’ new veteran backstop is one of the best pitch framers in the game.

MLB: Houston Astros at Tampa Bay Rays Kim Klement-USA TODAY Sports

Offense isn’t abundant in 2016’s free agent catcher market. In a class that includes Wilson Ramos, Matt Wieters, Jason Castro, Nick Hundley, Kurt Suzuki, and a handful of backups, teams are going to have to settle for alternative forms of production. On Tuesday night, the Twins did just that, reportedly agreeing to sign Jason Castro to a 3-year, $24.5 million dollar deal. The 29 year-old signal caller just completed his third consecutive sub-90 wRC+ season with the Astros, yet was still considered one of the best catching free agent options available this winter before being taken off the market. It’s time to dig a little deeper into what he specifically does that separates him from the rest of this free agent class, and see why the Twins rewarded him with a hefty contract.

Let’s check out one of Castro’s lesser-known points of production, pitch framing. Thanks to StatCorner, we have some interesting pitch framing numbers to go off of for catchers.

The site uses the following breakdown to rate catchers:

  • The number of called pitches caught total (N)
  • The number of called balls caught within the strike zone (zBall)
  • The number of called strikes caught outside the strike zone (oStr)
  • The percentage of pitches, caught within the strike zone, called a ball (zBall / nZ = zBall%)
  • The percentage of pitches, caught outside the strike zone, called a strike (oStr / nO = oStr%)

In essence, catchers want to have a low zBall percentage and a high oSTr percentage. League Average zBall rate is around 15 percent, while oSTr rate is closer to 7 percent.

A starting catcher that plays a majority of his team’s games will catch around 8,000 pitches per season. In total, there were 22 catchers who broke the 8,000-pitch mark in 2016. Of those heavy-load catchers, Castro graded out with the 3rd highest oSTr rate at 8.3 percent. Inversely, Castro had the 3rd lowest zBall rate at just 9.8 percent. In case you’re wondering, these numbers aren’t always perfect inverses of each other: Tucker Barnhart had the highest zBall rate at 15.8 percent, but only the 6th highest oSTr rate at 7.7 percent. Buster Posey and Yasmani Grandal were the only two catchers to edge out Castro for the top oSTr rate, with both of them tied for 1st at 9.0 percent.

Moving to the remaining free agent options, the metrics are not nearly as bullish on either Wieters or Ramos. Using the same 8,000-pitch sample size, Wieters finished at 17th in oSTr rate at just 6.7 percent, and Ramos finished just one spot ahead of Wieters at 6.9 percent. When we bring the sample size requirement down to 6,000 pitches caught, other available catchers like Kurt Suzuki and Nick Hundley come into the mix. Suzuki and Hundley finished 14th and 21st at turning pitches just off the plate into strikes. The takeaway: Castro was clearly the best pitch framing option available on the market today.

The Market for Castro

Besides the Twins, teams that could look for a catcher in free agency include the Orioles, Rockies, Nationals, Rays, Braves, White Sox, and Angels. Given Castro’s lack of offensive prowess, getting a third year in free agency is a nice deal on his part, and might indicate increasing awareness of the importance of framing on the part of teams. Even for catchers, we usually see them get paid after some kind of offensive spurt. Just in the last five years, we saw Jarrod Saltalamacchia, Devin Mesoraco, Francisco Cervelli, Yan Gomes, and Carlos Ruiz sign either extensions or for three years in free agency only after they had an offensive breakout. While the market has generally been paying catchers for their offensive value, their pitch framing and overall defensive abilities are what affect their team’s run differential the most over the course of a season, and Castro’s contract might be an indicator of the market catching up.

To evaluate Castro’s new contract, we have to find a comparable. In Russell Martin, we have another catcher whose defensive reputation overshadowed his ability with the bat. Here are the three seasons of both Martin and Castro leading up to their free agency.

At the time of their respective free agencies, Martin was a superior offensive player to Castro. Across the board, Martin has produced at a higher level offensively, and even produced a full 2 WAR more than Castro over the three year span. Even with the roughly league average production and excellent defensive reputation, Martin could only muster a 2-year, $17 million deal with the Pirates. It isn’t a reach to conclude that since Castro has signed for three years and a nearly equivalent annual value with the Twins, teams are starting to put a higher value on pitch framing.

How the Twins Improved:

While Kurt Suzuki has a fine reputation as an adequate backstop that can handle a pitching staff, the Twins needed to improve. In terms of pitch framing, Suzuki did leave a lot to be desired.

Here are Suzuki’s last three seasons in Minnesota:

Here are Castro’s last three years to compare:

Suzuki consistently graded out as a negative pitch framer for the Twins in all of the past three seasons. In order to understand how +Calls translates into runs, Stat Corner creates a run-added average for each catcher. In 2016, Suzuki accumulated -5.0 RAA, while Castro put up a robust 12.8 RAA. The 17.8 run difference amounts to almost 2 full wins over the course of a season, just by accounting for pitch framing. Already, the Twins have not only improved defensively behind the dish, but they’ve helped their young pitching staff in a crucial year for their development. Pitchers like Jose Berrios won’t actually be any better with Castro as their batterymate, but their results will likely be better, and building confidence is surely an important aspect of a pitching prospect’s growth. As the Twins look to mold their young core into a contender, every little advantage counts. Now, they’ll have that advantage on just about every pitch.