All that pitch-framing research is exciting, because it’s new, it supports an age-old idea, it seems to be meaningful, and it allows us to better capture the idea of a catcher’s real value. I’d say that was a true analytical breakthrough. One issue, though — however minor — is that not all pitchers are identical, and pitch-framing results can’t be taken to be 100% the responsibility of the catcher in question. It stands to reason it’s a lot more complicated than that, and it stands to reason there are pitchers who might be easier or more difficult to frame than others. You can probably think of a few off the top of your head. I think consensus is that Livan Hernandez has been relying on framers since about a month after he debuted.
What I’m not going to do here is identify the pitchers who are easiest and most difficult to frame. What I am going to do here is take a small step in that direction, by analyzing PITCHf/x data between 2008-2012. Instead of looking at this from a catcher’s perspective, we can look at this from a pitcher’s perspective, throwing to a number of different catchers on possibly a number of different teams. Not everything will average out, and in fact not everything will come even close to averaging out, but I’ll let the hard part of the work fall to someone smarter and more capable.
As I’ve alluded to a number of times, using stats readily available on FanGraphs, it’s simple to calculate an “expected strike rate”. You’re offered a total number of pitches, and a total number of strikes. You’re offered zone rate, and out-of-zone swing rate. It’s all easy, and then once you have expected strikes, you can compare that to actual strikes, in the hopes of seeing something. Every time, you will see something. Sometimes you might see something more surprising.
Zone rate is based on PITCHf/x data, and we have near-complete PITCHf/x data going back to 2008. What you’re going to see below are tables of data, showing pitchers and their differences between strikes and expected strikes per 1,000 called pitches. I looked at starters who threw at least 400 innings between 2008-2012, and relievers who threw at least 200 innings. A positive number means more strikes than expected strikes; a negative number means the very opposite of that. Interestingly, starters averaged a Diff/1000 of -18, while relievers averaged a Diff/1000 of -21. That is, based on PITCHf/x plate-discipline data, there haven’t been enough called strikes, at least over the last five years. So understand when you look at these tables that the league average is not zero.
It’s also interesting to note that the average has gotten closer to zero two years in a row, for both starters and relievers. For starters since 2010, the average has moved from -22 to -15 to -7, while for relievers, it’s moved from -25 to -19 to -11. This could mean nothing. This could indicate a change in the PITCHf/x plate-discipline data calculations. This could indicate greater receiving around the league. Or this could indicate a trend toward better umpire accuracy. We have no choice but to wait on further data.
To the top-10 tables now.
Starters, top 10, more strikes, 2008-2012
Starters, top 10, fewer strikes, 2008-2012
Relievers, top 10, more strikes, 2008-2012
Relievers, top 10, fewer strikes, 2008-2012
Obviously, this has not been separated from potential framing effects. Felix, for example, has stayed on the same team. Masterson has thrown a lot to Carlos Santana. As noted before, variables have not evened out, and I haven’t a prayer of being able to make them do so. These numbers are simply presented for your consideration, and you may do with them as you like.
The guy I find fascinating is Derek Lowe. Lowe leads everyone in Diff/1000 since 2008. But now let’s break this down year-to-year and compare Lowe’s Diff/1000 to the league-average Diff/1000 for starters:
Lowe’s numbers between 2008-2011 are almost impossible to fathom. He spent one of those years throwing to Russell Martin with the Dodgers, then three of those years throwing to Brian McCann with the Braves. Then, before 2012, he shifted to the Indians, with whom he threw to Santana and Lou Marson. Suddenly, Lowe was actually below-average, instead of otherworldly. And in parallel, Lowe went from being kind of able to strike batters out to being not at all able to strike batters out. This is the sort of thing that makes you think this is all more about the catchers than the pitchers. Via Texas Leaguers, here’s Lowe’s called strike zone for 2011:
Here’s Lowe’s called strike zone for 2012:
And here’s Masterson’s called strike zone for 2012, since Masterson and Lowe are somewhat similar pitchers who pitched for the same team:
Against lefties, Lowe used to dwell in and beyond the low-away quadrant. In 2012 he stopped getting so many of those strikes, so he had to change. His strikeout rate against lefties was cut in half. His strikeout rate against righties was also cut in half, and there’s a lot going on, here. This isn’t an article about Derek Lowe.
This is just an article to show some numbers. I think we’re at the point where we can acknowledge that pitch-framing is probably a real skill that some catchers have more than others. But not every pitcher on the mound comes with the same framing degree of difficulty. If Jamie Moyer throws a low fastball in the zone that gets called a ball, and if Felix Hernandez throws a low fastball in the same spot that gets called a ball, one of those is a little more forgivable than the other. Framing might not be hard, I don’t know, but framing some guys has got to be a relative challenge.
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