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Gauging the Effect of a Little Practice

Posted By Jeff Sullivan On January 14, 2013 @ 6:11 pm In Daily Graphings | 17 Comments

People will tell you that practice makes perfect. This is untrue, at least as far as it has to do with humans. Humans will forever be imperfect, and a better and more accurate saying would be “practice makes better”. If you’re trying to do something, and you practice it, you’ll probably do better than you would have had you not practiced it. This is the whole idea behind practice, so I’m glad we finally have this cleared up.

Major-league baseball players have practiced baseball. An awful lot! For years and years and years, on a regular basis, and you could even make the argument that games are just practice for future games. Everything is practice for the next such opportunity. What we can figure is that these players are better for having practiced, and without so much practice, they might and presumably would be worse. We can’t really measure the effect of practice, though, since they’re all practicing all the time. We don’t have a practice-less control group.

This is one area where pitchers come in handy. Whether you agree or disagree that pitchers ought to bat in today’s game, pitchers are fascinating to study as a group, and we wouldn’t have that information if they were all replaced by designated hitters. Pitchers can give us a glimpse into how people not selected for their offense might perform offensively in the major leagues. Pitchers, after all, bat thousands of times, and this gives us some pretty good samples. And pitchers can also tell us a little something about the effect of regular practice. Regular batting practice, that is, because we have an American League and a National League, and the leagues have different rules.

Your quick summary: pitchers in the National League will practice batting regularly. This is because pitchers in the National League bat. Pitchers in the American League will practice batting around interleague play, because that’ll bring their only opportunities. No sense in practicing it with a bunch of other AL games coming up. Incidentally, this just got me wondering about how things might change down the road, now that interleague play is a little more scattered and a little more frequent. Will AL pitchers start to catch up to NL pitchers at the plate? Something to monitor! But not what we’re monitoring now.

By examining the differences between AL pitchers hitting and NL pitchers hitting, we can learn something about the effect of all that practice. It isn’t perfect, of course. Many AL pitchers have played previously in the NL, so they have previous big-league hitting or practicing experience. And pitchers have all hit in the past, and they’ve probably been good at it. NL teams might select for better-hitting pitchers, since it’s a consideration to them and not to teams in the AL. I’m kind of skeptical that this matters in reality, but it might and I don’t know for sure that it doesn’t.

So that’s enough words — let’s look at some numbers. I gathered data for 2008-2012, dating back to the beginning of the reliable PITCHf/x Era. I’ve got three tables, covering, generally, opposing pitcher approach, batting results, and batting discipline. Table one:

League PA FA% F-Strike% Zone% Pace
AL 1593 73% 73% 58% 18.3
NL 28342 71% 69% 56% 18.8

AL pitchers have seen a few more fastballs, which is something you’d probably expect. They’ve also seen more first-pitch strikes, and more pitches in the zone, and opposing pitchers have worked a little more quickly. All of this makes perfect intuitive sense. NL pitchers know that NL pitchers practice batting pretty regularly. They also know that AL pitchers do not, so they’re more willing to come right after them. Why be intimidated by an AL pitcher at the plate? Provided that AL pitcher isn’t Felix Hernandez, and provided you aren’t Johan Santana. The differences here, though, are not particularly dramatic. As a general rule of thumb, pitchers don’t respect pitchers batting. They just respect AL pitchers batting a tiny bit less, which is warranted.

Moving on:

League HBP% SH% BB% K% wRC+ GB%
AL 0% 11% 3% 41% -23 65%
NL 0% 11% 4% 34% -11 60%

No AL pitcher has been hit by a pitch since 2007. Over the past five years, 69 NL pitchers have been hit by pitches. There’s no difference in the sacrifice bunting rate, so bunting practice might not make a whole lot of difference. This would require a deeper and more specific investigation. You can see that AL pitchers have struck out far more often. They’ve produced inferior results. They’ve put the ball more often on the ground. The last one is of some interest; the others are pretty predictable. AL pitchers have grounder-heavy swings. This is probably because they have bad swings. It might be because, as a group, they try to just slap the ball on the ground in order to make some sort of contact. Meanwhile, it’s not like NL pitchers go up there and line the ball all over the yard.

And finally:

League O-Swing% Z-Swing% Swing% O-Contact% Z-Contact% Contact%
AL 34% 53% 45% 51% 75% 67%
NL 34% 55% 46% 53% 80% 71%

Here we can see why AL pitchers strike out more often. They make contact less often, at both balls and strikes. They don’t actually swing at balls more often, which is interesting, but their judgment is poor, in terms of swings at strikes vs. swings at balls. Practice doesn’t seem to have much of an effect on discipline, as we can observe here; it does seem to allow the pitchers to more often make contact with the baseball. The contact rates are all poor, but they’re also all different.

Which might, again, be because NL teams might select in part for hitting ability. But presuming they don’t really do that, and presuming the AL and NL pitcher sample pools are of roughly equivalent offensive talent levels, then we can see above how practice has been helping, or how a lack of practice has been hurting. NL pitchers have out-hit AL pitchers. A big part of this is because they have struck out less often. They’re still very bad, and they still strike out too much, and what happens with pitchers can’t really be applied to position players for whom hitting is genuinely important, but as far as the effect of practice is concerned, this is one approximation of one thing. There’s a difference that we might be able to chalk up to taking more regular BP and just thinking about batting more than a handful of times a season.

It will be interesting to see if things change as interleague play changes. That is, if the pitcher-batting phenomenon isn’t eliminated. That’s for another time in the future, and I’ll just have to wait like all the rest of you.


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