Simple Sabermetrics: Plate Discipline

17 inches wide.

As we continue this Simple Sabermetrics series of posts, we’re going to look not just at a single stat, but instead a collection of statistics which are a fantastic tool for evaluating a hitter’s true skill at the plate. Cast all your free swinging tendencies aside, because we’re looking at plate discipline.

Plate Discipline statistics tell us how good a player is at making contact with pitches. They also tell us how patient a player is at the plate. Below is the wide number of statistics this entails:

"O-Swing%: The percentage of pitches outside the strike that a batter swings at.O-Contact%: The percentage of pitches outside the strike zone that a batter makes contact with.Z-Swing%: The percentage of pitches inside the strike zone that a batter swings at.Z-Contact%: The percentage of pitches inside the strike zone a batter makes contact with.Swing%: The overall percentage of pitches a batter swings at.Contact%: The overall percentage of pitches a batter makes contact with when swinging the bat.SwStr%: The percentage of total pitches a batter swings and misses on."

So, actually, they really are straight-forward; it’s just the sheer number of them that overwhelms fantasy owners who want to use them as a research tool. So let’s jump straight into an example player, looking at Matt Carpenter, who has fantastic bat control and who rarely swings at bad pitches. Here are his plate discipline rankings among qualified MLB hitters at the time this post is being typed:

"O-Swing: 5th (21.6%)Z-Contact: 6th (95.3%)Swing %: 1st (37.6%)Contact %: 10th (89.5%)Swinging strike rate: 8th (3.9%)"

The type of plate discipline we looked at above? That’s not swinging at many bad pitches and that’s putting the stick on good pitches. Coming up through the minors, Carpenter was always known as having great plate discipline and it certainly plays out as you look at the numbers he’s putting up.

How about another example that may surprise you? Marco Scutaro leads baseball in swinging at the fewest pitches out of the strike zone. His O-Swing is 19.8%. In 8th place is Dan Uggla, who has an O-Swing of just 23.1%.

Uggla, a player who is notorious for his hacking, actually stays in the zone better than almost anyone, better than Buster Posey, Mike Trout, Paul Goldschmidt and Joe Mauer, the man with the discerning eye. Pitchers try to get Uggla to chase, but he doesn’t fish. He doesn’t hack as much as one would think, based upon his strikeout rates.

But Uggla strikes out in a third of his appearances. This brings us back to Marco Scutaro.

"Scutaro O-Contact: 88.7%Uggla O-Contact: 45.3%"

So…that’s a big difference. While Uggla actually doesn’t chase many pitches, he flails and misses on almost all he does chase. Evidently, it’s excellent news that Uggla has gotten his vision corrected. WIth strikeouts skyrocketing in baseball, it’s possible that a batter’s ability to NOT strike out is becoming more important, in terms of hitting, than walks. A hitter’s ability to either make contact or not chase pitches (not strikeout) is more critical than ever. But let’s not get sidetracked.

Instead, let’s take a look at what you should expect in terms of league averages. The averages below will give you a handy baseline to provide context and give you a nice comparable as you use plate discipline statistics as part of your sabermetric tool belt.

"O-Swing 30%Z-Swing 65%Swing 46%O-Contact 68%Z-Contact 88%Contact 81%SwStr 8.5%"

I hope you find plate discipline statistics  interesting, because I want us to be friends and I can spend an hour perusing the plate discipline leader boards. But besides the trivial nature of seeing which players swing most often at pitches in the dirt, these numbers are EXTREMELY helpful in researching players for your fantasy baseball team. I’ll share 4 ways:

1. Target players who don’t chase. A simple scan of the previous year’s leaderboards easily identifies players who are good at laying off pitches out of the zone, which has a high correlation with success at the plate. Add this step as part of your pre-draft research process, lifting players with strong plate discipline a slot or two on your draft cheatsheet.
2. Identify players with an intentional adjustment at the plate. If you are perplexed about a change in a player’s performance, look to plate discipline statistics for a potential answer. Perhaps they are in a change of approach at the plate, intentionally trying to swing at fewer bad pitches, for example.
3. Look for decreases in skill. As players age the have slower reaction times at the plate. By scanning contact and swinging strike percentages and noticing a rise, you can potentially determine if age (or injury) is catching up to a player.
4. Spot players who are hitting over their heads. Plate discipline statistics are also helpful in season. A player jumping out to a strong start may not be able sustain that pace if his plate discipline statistics are all tracking well over his career averages. A quick comparison of career versus current numbers will tell you if something is off and a regression is due.

Those are just 4 of the dozens of ways that plate discipline statistics are useful in researching fantasy baseball. I hope this simple tutorial opened your eyes to the possibilities. Home plate is  an irregularly shaped pentagon, measuring 17 inches wide. A batter who has an eye for those dimensions is a player you probably want on your fantasy team.