Saturday night in Seattle, the Mariners were playing the Rangers, and the score was 1-1 going into the top of the eighth inning. Carter Capps relieved Joe Saunders, and the broadcast warned that Capps shouldn’t walk leadoff batter Craig Gentry, because Gentry is one of the quicker runners in the league. Also because you shouldn’t walk anybody if you can help it. Capps subsequently walked Gentry, and Gentry scored, and that run would prove to be the winning run in a 3-1 final. Gentry walked on seven pitches and a full count.

It was a walk not without its controversy, although it looks like a bigger deal now than it seemed at the time. With the count 2-and-2, Capps threw Gentry a fastball in the low-away quadrant that easily could’ve been called strike three. Gameday shows that the pitch was within the strike zone, and during the game other strikes were called in the area. The pitch was ruled ball three, and the next pitch was a far less controversial ball four. Hence the walk, hence the run, hence the loss. It didn’t sit very well with Carter Capps, not that the one pitch was the reason the Mariners lost the ballgame.

The pitch in question:

Now, if you’d like to see it in slower motion:

The little pixelated black cloud was not a part of the baseball game. Either my .gif optimizer didn’t like the screen freeze, or I’m picking up on a ghost. Either way, it’s not worth pursuing on FanGraphs.

The guy behind the plate was Kelly Shoppach, not noted across-the-board disappointment Jesus Montero. Here are screenshots of the target and the pitch around the front of home plate:

All right, those are all my images. Now, it’s evident that the fastball wasn’t thrown right down the middle. It was something of a borderline pitch, even though it was more strike than ball. Nobody here is going to be absolutely correct. If this pitch is called a strike, maybe the Rangers don’t score, and maybe the Mariners win. After this pitch was called a ball, the Rangers scored, and the Mariners lost. One can understand why the Mariners might be a little peeved. A few tweets on the subject:

Carter Capps and Carl Willis both went back and watched the 2-2 pitch from last night. They both felt it was a strike. — Ryan Divish (@RyanDivish) April 14, 2013

Willis: “I think his command is going to improve and I think it will help him get some of those calls.” — Ryan Divish (@RyanDivish) April 14, 2013

Willis said that Capps deceptive delivery, throwing across his body and velocity can make it tough for umps as well as hitters. — Ryan Divish (@RyanDivish) April 14, 2013



While I’ll own up to being a Mariners fan, my intent here is not to complain about a questionable pitch call that went the wrong way. I should hope that people don’t think I’m ever biased in the Mariners’ favor; just because I’m a Mariners fan doesn’t mean I actually like them most of the time. My intent here is to highlight something about how and why some pitches get called in some ways.

Again, this was a close pitch. In the past, when there were close pitches that went the wrong way, people blamed the umpires. Then, some time ago, many of us started paying closer attention to pitch-framing. Pitch-framing has at least taken certain corners of the Internet by storm, and now people are keeping an eye out for it. When a close pitch is called a strike, people credit the catcher. When a close pitch is called a ball, people blame the catcher. Framing makes a difference, and what people have been conditioned now to believe is that framing makes a huge difference.

Framing is a factor. When a pitch is thrown and taken, there are a variety of factors influencing how the pitch is judged. Framing is one of them, but there are so many others, and let’s watch that .gif from above again:

That’s a fastball, and Shoppach didn’t receive it poorly. Maybe he stabbed a little too much, I don’t know, but Shoppach kept his body quiet and stuck the ball when it arrived. He still didn’t get the call. There probably wasn’t a lot Shoppach could’ve done to make that a strike, even though the pitch seems to have caught the zone.

If a missed call isn’t the catcher’s fault, it has to be the umpire’s fault. Heck, even if it is the catcher’s fault, it’s still the umpire’s fault. The umpire is just supposed to call the strike zone, and now we’re talking about the good ol’ human element. It’s been evident since the very dawn of baseball that humans make imperfect arbiters, but consider this a sympathetic exercise. In this instance, it isn’t an umpire calling a pitch on the edge of the zone. It’s an umpire calling a 97 mile-per-hour Carter Capps fastball on the edge of the zone.

Not all pitches will be able to be judged with equivalent accuracy. That wouldn’t make sense, because judgments are based on how pitches look, and different pitches look different. Look at those tweets above and consider the words from Mariners pitching coach Carl Willis. He isn’t wrong that the pitch was probably a strike, but he also isn’t wrong in that Capps presumably makes things more difficult than they already are. Capps throws pitches that move fast and move a lot. He also throws them from an unusual arm angle, so not only will the umpires get a different look; his fastball and slider won’t break like a conventional pitcher’s fastball and slider. A guy like Capps is weird to see from behind the plate, so a guy like Capps is probably destined to end up with something of an inconsistent strike zone.

I don’t have readily accessible information about different arm slots and throwing mechanics. I do have readily accessible velocity information, right here on FanGraphs. Let’s concentrate on average fastball velocity. Now, I’ve written before about a home-brewed stat called Diff/1000. This is the difference between strikes and expected strikes per 1,000 called pitches, based on the PITCHf/x plate-discipline data available on these pages. A negative Diff/1000 means a pitcher got a smaller strike zone. A positive Diff/1000 means a pitcher got a more favorable strike zone. Got it? Got it.

I grouped data going back to 2008, separating starters and relievers. For starters, I set a 200-inning minimum, and for relievers I set a 100-inning minimum. For all pitchers, I calculated Diff/1000. For starters, the correlation between average fastball velocity and Diff/1000 is -0.26. For relievers, the correlation between average fastball velocity and Diff/1000 is -0.34. These aren’t real strong, but they are meaningful, and they don’t account for catcher identity. What the numbers show is that, the harder a guy throws, the less favorable a strike zone he gets.

In general, not in every case. But there’s a reason guys like Jamie Moyer and Livan Hernandez show up with bigger zones. There’s a reason guys like Brandon League and Ronald Belisario and Mark Lowe show up with smaller zones. Pitches that move faster are harder to evaluate. So are pitches that move more rather than less, I’m guessing. So are pitches thrown from unusual arm angles, I’m guessing. It seems to help to have a reputation for good command. That makes things easier for the catcher, and to some extent the umpire will be biased. But there are a lot of factors at play, here, and one has to understand what it’s like to be standing behind a catcher. Some people’s pitches are just easier to evaluate than others, and there’s nothing an umpire can do to change that truth. A guy who throws 95 will have greater strike zone error bars than a guy who throws 85.

Of course, this isn’t independent of pitch-framing. It’s also harder to receive a guy with wicked stuff, and then that’ll have its own influence. But the bottom line is that the fate of a called pitch is never entirely up to the backstop. He can exert some influence over the umpire, but it’s only partial, and the umpire will have more trouble with a nastier pitch than he will with a less-nasty pitch. This is probably what happened with Carter Capps against Craig Gentry on Saturday night. If you want to rationalize it, you can think of this as a small tax for possessing a higher-quality repertoire. In some small way it helps to even the playing field. Capps might throw to a smaller zone, but he also gets to throw like Carter Capps. Most people would take that trade. Is it a trade that should need to be made? Everyone, in theory, should be able to throw to the same strike zone, but as long as things are the way they are, that’s just impossible. It’s impossible, for so many reasons.