D-backs catchers, a 2016 vs. 2017 comparison: By the numbers

The first signs that the Diamondbacks’ revamped front office would be using analytics as a tool to guide their decision-making came with the turnover at the catcher position.

Arizona moved on from Welington Castillo’s bat — a very good one at that — and went with a three-headed monster by signing veterans Jeff Mathis and Chris Iannetta. The D-backs also retained Chris Herrmann, a versatile player who could spend some time in the outfield and bring power at the plate.

Of late, it’s Herrmann who’s overseen the stellar pitching of Robbie Ray. But Mathis and Iannetta have held their own behind the plate, and with a bat in their hands — it was Iannetta who on Thursday recorded a career-high seven RBI in a win over the Padres.

Here is a look at the catcher position for Arizona in 2016 compared to 2017, by the numbers.

3.64

Although it’s not entirely on the signal callers behind the plate, all three Diamondbacks should be given plenty of credit in the immense improvement in pitching. The D-backs have the fourth-lowest ERA in Major League Baseball at 3.64 entering play Saturday, which is certainly a big reason the team has jumped out to a 37-26 start. There’s not even much of a comparison to how the staff performed last year, where they were dead last in all of baseball with a 5.09 ERA. Adding some defensive experience at the catching position will do that.

2.93

On the subject of good pitching: The D-backs battery is striking out more hitters and walking fewer this year than last. Their strikeout-to-walk ratio sits at 2.93 in 2017, compared to 2.18 last year.

96

Ninety-six is the rank of Castillo in terms of Baseball Prospectus’ “framing runs” statistic from last season. That’s out of 104 catchers. This year, Mathis is ranked eighth in the statistic while Iannetta follows as the ninth-best pitch framer. Herrmann ranks 64th.

.257 vs. .181

That’s the combined batting average drop-off from the Castillo-heavy catching position from a year ago to the 2017 average between the D-backs’ trio.

.312 vs. .196

That’s the drop off from last year to this year in the D-backs catchers’ BABIP — batting average on balls put in play. It’s a representation of how often a hitter is getting a base hit when he’s making contact with the ball, and the formula doesn’t count home runs or sac flies.

0.63 vs. 0.34

The RBI-per-game of the three D-backs catchers at the plate is well below what was being produced last year.

18

Despite the improved ERA and bolstered pitch-framing, Arizona’s catchers rank just 18th in baseball in opposing stolen base percentage. The D-backs finished fifth in MLB in that category last year at 64.3 percent, but this year, baserunners steal safely on 73.8 percent of their attempts.

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