As we’ve covered extensively in previous articles, Francisco Cervelli picked up last year where Russell Martin left off, earning a multi-year contract extension that will keep him under team control through the 2019 season. Cervelli’s .295/.370/.401 (119 wRC+) line in 2015 was critical to the team’s success, and prior to his injury, he had managed to hit for a decent .257/.373/.293 (95 wRC+) performance so far this season.

That injury, in combination with some aches and pains for backup Chris Stewart, have created somewhat of a revolving door for the Pirates at the catching position over the last couple weeks. Journeyman and former Pirate Erik Kratz was acquired from the Angels, and Jacob Stallings was recently promoted from Indianapolis when Stewart was unable to start due to a knee injury.

Completely replacing Cervelli’s offensive skill set was not a reasonable goal, but Stewart’s production in his two seasons with the Pirates (.292/.340/.336, 92 wRC+) is more than serviceable for a backup catcher. What matters more for the Pirates, though, is what the catcher does behind the plate rather than in the batter’s box.

As those who’ve read Travis Sawchik’s Big Data Baseball know, acquiring Martin was indicative of a new run prevention philosophy that placed an emphasis on catcher defense, and in particular the ability to obtain extra strikes through pitch framing.

The importance of pitch framing is not new to baseball, but the advent of Pitch f/X allowed for better quantification of just how valuable a skill it is for your catcher to have, as Mike Fast (now working for the Astros) described in various Baseball Prospectus articles as early as 2011.

What the analysis shows is that pitch framing can make a more substantial contribution to a team’s success — positive or negative — than expected. Controlling the running game, blocking balls in the dirt, etc., while important, are not nearly as valuable as the ability (or inability) to get extra called strikes, at least in terms of what we can presently quantify.

Martin was among the best pitch framers in the NL in each of his two seasons with the Pirates, and Cervelli found an even higher level last year, finishing 2nd in Baseball Prospectus’ framing runs behind only the Dodgers’ Yasmani Grandal.

Martin and Cervelli

To put it in terms of wins added rather than runs, Cervelli’s pitch framing skills alone were worth essentially two extra wins for the Pirates in 2015.

Losing those framing skills for 4-6 weeks may not seem like a big deal, but with the Pirates clinging to hopes of competing for a Wild Card spot, every marginal win matters. While they are capable framers, unfortunately, Chris Stewart and Erik Kratz are little competition for Cervelli’s skill set:

Statistics courtesy of
Statistics courtesy of

I used the Statcorner numbers in this case rather than the Baseball Prospectus model because “calls per game” is a useful demonstration of Cervelli’s value. Only Stewart’s 2013 season comes close to Cervelli’s 2015 production on a per game and aggregate basis, and it would seem to be an outlier relative to his and Kratz’s recent performances.

Three quarters to a full extra strike per game is not a huge difference, but it does matter, particularly to a pitching staff that has one of the worst strikeout rates (14th at 18.3%) and one of the worst walk rates (12th at 9.5%) in the National League. Those 20 or 30 missing called strikes while Cervelli is out may be sorely needed by a rotation and bullpen that doesn’t seem to be able to get outs as efficiently as in the past.

Both Stewart and Kratz are skilled enough to be at least average compared to the other options available on the waiver wire, but their skills do not appear to be as valuable as what Cervelli can do behind the plate when he is fully healthy.


While Stallings has received an opportunity for some major league experience in recent days, it’s unreasonable to expect him to stay long with Chris Stewart in seemingly improving health.

Not that anyone was expecting him to, but Stallings cannot make a compelling case to remain in Pittsburgh based on his pitch framing skills. Consider these numbers from his past two seasons:

Jacob Stallings

In a more perfect world, Elias Diaz would have gotten an opportunity for regular starts with the Pirates in Cervelli’s absence. But as our subscribers already know, Diaz is recovering from elbow surgery and will not be available until after the time that Cervelli should return.

To his credit, the numbers show that the scouting reports of Diaz’s defensive skill are not overblown. He has been a capable pitch framer at both of the levels we have Pitch f/X data for:

Elias Diaz

Unfortunately for the Pirates, it seems that there are no easy solutions at the major or minor league level for replacing Cervelli’s production, particularly as it applies to his ability to manipulate the strike zone. I suspect that the pitching staff in particular is hoping for his speedy recovery and return to the lineup.

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  1. There was a ton more variability in the framing statistics than I expected. I thought framing was pretty replicable from one season to the next, and if one is catching every 4 out of five days, there is a huge sample size in terms of actual pitches. Any reason behind variability from one year to another?

  2. For a team that relies on stats, clearly the extension of Cervelli was made due to his defense. I am not in the camp the extension was necessary due to his drop off in hitting. But 31 million for a at best Ok offensive catcher and defensive catcher. Hopefully he can be a big help to the young arms that are coming and I am sure that was the key reason for the extension.

  3. Of course anytime you lose a starting position player there will be a drop off. In this case, it’s mostly offensively since Stewart and a Kratz are equivalent to pitchers when it comes to hitting. With that being said, Cervelli was one of the team’s biggest disappointments before he got hurt. He stopped hitting right around the time of his extension. Pitching is the issue…and it was bad when Cervelli was playing.

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