May 17, 2003

The Catcher Arms Race

What the Intimidation Factor Means for Catcher Defense

by Michael Wolverton

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A few items from the mailbag generated by The Man With the Golden Gun: 2002, which ranked baseball's best catcher arms using a measure of Stolen Base Runs Prevented (SBRP):

I was glad that you concede that your analysis is biased against players that have a solid reputation. It strikes me as a limited phenomenon anyway. Only the real newbies are likely to get much of a bump from extra throwing opportunities against uninformed opposition. All catchers with good reputations will benefit by the comparison to the Piazzas of the world who have so many attempts against them.

-- CDS

I did note in the original article that a catcher's reputation influences the number of steal attempts against him, and that the number of steal attempts in turn affects his Stolen Base Runs Prevented rating. But I wouldn't say the analysis is biased against players that have a solid reputation.

It all comes down to what you're trying to measure, skill or value. If you're trying to measure skill--how strong, accurate, and generally impressive a catcher's arm is--then yes, you would want to give extra credit to those catchers who prevent runners from even attempting to steal. But SBRP is trying to measure value--how many runs the catcher prevents the opposition from scoring through his control of the running game. And if run prevention is what you're after, shutting down steal attempts isn't necessarily a good thing. In fact, you could make a strong case that it's a bad thing.

That's because steal attempts seem to be a net negative for offenses league-wide. (I'll say in a minute why I have to use the qualified "seem to be.") On average, a stolen base is worth only .16 runs to the offense, but a caught stealing costs the offense .49 runs. (Those numbers come from the work I did, but other people have come up with similar values.) That means that running teams need to succeed about three times (.49/.16 = 3.1) for every time caught stealing just to break even in the running game.

But major league teams don't come anywhere near that break-even rate on the basepaths, coming much closer to two successful steals for every caught stealing than three. Last year major leaguers stole 2750 bases and were caught 1282 times, for a success rate of 68%. (Contrary to popular belief, the numbers don't differ much between the AL and the NL.) Also, major league runners stumbled into 330 pickoffs, many of which involved would-be basestealers leaning the wrong way. Add it all together with the run values above, and you get that the running game cost major league offenses a total of 350 runs last year.

Now, let's imagine your team has an uber-Pudge, a catcher with an arm so fearsome that no team ever dares to run on him. That sounds good on the surface, but actually what he's doing is robbing the team of its share of those 350 runs. You'd be better off with Joe Average Catcher, who gets plenty of steal attempts and who throws out about 30% of them--enough to take advantage of league-wide over-aggressive baserunning and prevent some runs for the defense.

Of course, uber-Pudge doesn't exist. Even the most fearsome arms in the league get plenty of steal attempts against them, and because of those steal attempts, those arms are more valuable than Joe Average's. But you don't want to award them extra points for any steal attempts their reputations prevent, because more steal attempts allow him to prevent more runs -- i.e., they make him more valuable. Given a choice between a 50% CS catcher who sees a steal attempt every 14 innings (Ivan Rodriguez in 1996), and a 50% CS catcher who sees a steal attempt every 19 innings (Rodriguez in 2001), you'd prefer the former every time.

Now the disclaimers. There are potential benefits of stopping the running game that I'm ignoring here. In particular, there's the hit-and-run, which definitely has some value to offenses in taking extra bases and (more importantly) staying out of double plays. Strong-armed catchers who prevent steal attempts presumably also reduce hit-and-run plays to some degree, saving a few runs in the process. I don't know of anyone who's studied hit-and-run plays--either the benefit of them or the effect of the catcher on them--but it could be worth a look. My guess is that the overall effect would be small, but that's only a guess.

How come Ramon Hernandez wasn't considered? Even through last year, he had a reputation as a weaker-armed catcher, but the stats don't reflect that. In 1100 innings, only 45 bases were stolen off of him, while he threw out 30 would-be base-stealers, for a CS rate of 40%.

Compare that to his previous year, where there were 98 SB and only 44 CS in a similar amount of innings, and it looks like Hernandez has vastly improved.

-- DC

You're right that Hernandez deserves some mention for the improvement in his throwing. He put up mediocre numbers in his first two seasons, and then hit bottom in early 2001 when he started off just 3-for-33 in catching baserunners. The A's worked with him on his release time and footwork, and he regrouped to finish with solid end-season numbers that year, better numbers last year, and even better numbers so far this season.

But I really wanted to use your email to make a broader point about catcher caught stealing numbers. The numbers you cite for Hernandez are the caught stealing numbers you'll find at all the major stats sources, including ESPN.com and MLB.com. And you're right--if those were Hernandez's actual caught stealing totals--then he would have been among the top finishers in SBRP last year.

But all those sources include pitcher caught stealings in the catcher's numbers. (A pitcher caught stealing occurs when the pitcher picks a basestealer off first, and the runner continues to second and is thrown or tagged out.) Hernandez actually threw out only 21 would-be basestealers last season; the other nine CSs that ESPN & Co. credit him with occurred on plays where he didn't even touch the ball.

You could make an argument that pitcher CSs tell us a little bit about the catcher behind the plate. But I think including pitcher CSs in catcher numbers does much more harm than it does good, so I don't include them. I don't know of a comprehensive online source for catcher-only CS numbers (I get mine from box scores). STATS, Inc. has them, but only for this year and only for a handful of catchers.

If Bengie Molina is now the Man with the Golden Gun, does that mean he acquired a 3rd nipple as well? Maybe La Rue had to hand his over... or maybe extra nipples just accumulate on one's body like gold gloves do on shelves. Pudge must look like a sow...

-- RK

I have no idea what you're talking about, RK. On a completely unrelated note, I'll mention that our original plan for the prize was a week of devoted servitude by Herve Villechaize and an evening with Maud Adams (Mmm...Maud Adams). Unfortunately, the idea fell through when we discovered that the late Villechaize was, well, late, and when Adams wouldn't return our calls. So we went with plan B for the prize: glowing praise and our highest esteem. I'm sure Molina would prefer that anyway.