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Diamondbacks shake up catching situation, non-tendering Welington Castillo and signing Jeff Mathis

Part of the reason why I wanted the Diamondbacks to look at a possible Derek Norris trade was because of pitch framing ability. I figured with a more analytically-inclined front office that pitch framing skills would play into the catching situation. While Castillo posted 1.7 fWAR/2.4 bWAR, the Diamondbacks were not comfortable paying him a likely $6M. As a result, they elected to non-tender Castillo and likely use the savings to improve the team in another area like the outfield or the bullpen. The Diamondbacks didn’t waste any time right afterwards as they signed Jeff Mathis on a 2-year, $4M deal. The money suggests that Mathis will be a backup in Arizona, although I’m not sure if the team will add a starting catcher in the next week.

The biggest reason the team likely went for Mathis was his ability to frame pitches. Mathis’ framing saved 4 runs above an average catcher, and 7 runs better than Castillo. Mathis is the classical catch and throw guy that most teams look for in backup catchers and has a career 49 wRC+, which would be bad for Nick Ahmed standards, so it’s clear the team isn’t getting an upgrade in production. Mathis will likely be the opening day starter at catcher, but not the primary starter, since the team will likely have him catch Zack Greinke starts and depending on the specific order of the rotation (I was thinking Greinke then Walker) potentially Robbie Ray as well. Mathis’ contract is pretty reasonable for backup money as he’s making roughly $2M per season.

I would like to see the team look at a potential catcher in the FA market because I’m not convinced that Herrmann should stick back there. While his bat was more productive in less than half the plate appearances to Castillo, his defense is very questionable. Herrmann is very athletic for a catcher, but his pitch framing skills are very suspect as he was -5.6 runs above average in terms of framing. Jumping from 29 starts to possibly 90-100 offsets the number of runs saved framing that Mathis has over Castillo. I like Herrmann more as a backup 1B/corner OF type because of his bat and I’m hoping the team is able to find someone who can be the primary catcher. If the current roster is the Opening Day roster, I think we’ll see a Herrmann-Mathis platoon for the 130 games that Zack Greinke doesn’t start.

Another potential reason for Castillo’s early exit comes down to how well the pitching staff performed with him behind the plate. During his time in Arizona, the average pitcher RA/9 was 5.04. Other catchers were 4.83. To add further context, Castillo’s catcher’s ERA was 5.04 and Herrmann was 4.34. The difference is very significant, as it suggests that Castillo was doing a terrible job of calling games and working on the game plan. With a young pitching staff aside from the team’s opening day starter Zack Greinke, I prefer the option of having a catcher better suited to handle the pitching staff. Yesterday they added a catcher whose catcher’s ERA was 3.28 with the Miami Marlins. Mathis caught better pitchers in Miami than he will in Arizona, but I’m confident the pitching staff won’t post anywhere close 5.04 ERA when he’s behind the plate.

So how would the Mathis signing affect the team assuming an obvious dropoff in WAR at the catching position? The obvious answer would have to come from the rotation. With Jeff Mathis, who is a better game caller and pitch framer than Castillo, that should have a positive impact on a starting rotation that posted a collective 2.7 bWAR. That figure ranked 29th in MLB, with only the Twins 1.8 bWAR being less. Taking out batted ball luck and poor defense, the team ranked 21st with an output of 8.0 fWAR. Putting Mathis behind the plate for 60 or so games could swing an additional 50 or so calls the Diamondbacks way. The biggest difference in baseball is the difference between a 2-1 and a 1-2 count. Changing a few of those calls should put the pitchers in a better position to get more favorable outcomes.

In addition to the rotation, the team has a very young bullpen. There are four high ceiling relievers in Jake Barrett, Jared Miller, Enrique Burgos, and Jimmie Sherfy, all of whom have less than stellar command. In addition they have some young and very useful relievers in Andrew Chafin and the unit could potentially be getting a boost should Patrick Corbin being moved to the bullpen as well. The bullpen, which was supposed to be a strength of the 2016 team and for the first half of the season was OK, struggled down the stretch and needs veteran leadership to anchor the back end of the bullpen. Mathis makes sense as a late-inning defensive replacement behind the plate in critical games, such as the rubber match of the series or a chance to secure better position should the team somehow find itself into contention.

Pitchers like Robbie Ray and Zack Greinke underperformed their FIPs in 2016, with Greinke’s due to poor sequencing and relief and Ray due to a high BABIP. Both posted a combined 5.2 fWAR and 2.9 bWAR. Ray wasn’t the only pitcher to significantly underperform his FIP as Archie Bradley managed to pitch towards a league average FIP despite a 5.00+ ERA. Bradley, like Ray and Greinke, was the victim of poor sequencing and defense. So far, the team hasn’t made too many moves to fix the outfield defense, but the offseason is young and there are still moves to make in that department. As for Jeff Mathis, we should expect him to provide stellar defense behind the plate and leadership to the clubhouse that is in severe need of some.