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Randal Grichuk's "Improved" Plate Discipline

In which the author complains about a narrative which has been bugging him for quite some time.

Jeff Curry-USA TODAY Sports

The news of the day is, obviously, about Carlos Martinez. And no, I don't want to talk about it. Too raw, too sad. No thank you.


I'm playing a game called Little Inferno at the moment. I picked it up on a Humble Bundle sale at some point in the past, and never quite got around to playing it. You should play it. I won't say anything about it, other than the recommendation.

I can also recommend listening to Blur's "Best Days" while playing it; that's what I was doing immediately before starting to write this column. It feels like full autumn in my head, even if the outside temperature still smacks of summer's end.

Other people wouldn't like to hear you,

If you said,

That these are the best days of our lives.

Other people turn around and laugh at you,

If you said,

That these are the best days of our lives.


I believe I've mentioned it before, but I am an avid podcast listener. Much of the music I used to listen to while avoiding interaction at work or while toiling away at the gym has been replaced by podcasts, both because I am now an old man and podcasts are the Generation Y version of the AM talk radio of our father's trucks, and also because podcasts silence my mind in a way music never could hope to, functioning not only as a distraction but an outright buffer against thoughts both bitter and sweet, giving me something close to silence, the only thing I suppose I really wish for out of life.

Anyhow, Derrick Goold and the guy who took Bernie Miklasz's place at the Post-Dispatch have revived the Best Podcast in Baseball moniker, which I was unaware of until a whole bunch of new episodes popped up in my feed not too long ago. So I queued up a random one of them this morning while jumping rope, and a thing caught my attention.

The thing in question was a discussion of Randal Grichuk, and how he really took a huge step forward this season, consolidating the gains the club saw in spring training. Specifically, the gains he made in improving his contact rate and command of the strike zone. The emphasis, of course, is mine, because I found this particular narrative both fascinating and downright galling, considering what we know about Randal Grichuk as a hitter. It's not the first time I've heard this narrative, either; Goold himself has stated the same thing in other podcasts and interviews, and various radio types have put it out there as well.

The problem with this narrative, that Randal Grichuk went home over the offseason and substantially improved himself as a hitter in terms of strike zone command and reducing the swing and miss in his game is that it is complete and utter bullshit. Great steaming piles of it, in fact, baking in the sun.

First things first: the following is a fact, that Randal Grichuk's strikeout rate in 2015 is actually a fair bit worse than it was in 2014. To wit, his 2014 K% was 26.7%, which is really quite bad. This season, it's ballooned to 31.0%, which is positively Reynoldsian. So, if one wanted, one could simply point out to this narrative that Randal Grichuk is striking out more now than he did last year, which would seem to spit in the face of the idea of the player whose contact skills, plate coverage, and command of the zone have improved. However, just going with one number, even one as seemingly relevant to this discussion as K rate, is not good enough. So if we dig deeper, perhaps that strikeout rate will prove somewhat misleading, and we will find that Grichuk has, in fact, improved the things we are to believe he has improved.

If a player had really improved markedly in terms of his command of the strike zone, what would we expect to see? Well, for starters, I would think we should expect to see a reduction in his tendency to chase pitches out of the zone. It makes sense, right? Matt Carpenter is the very epitome of a player with excellent strike zone command, and one of the defining characteristics of said mastery is his refusal to swing at nearly anything outside the zone, occasionally to his own detriment, as we've seen a rather shocking number of balls called strikes on the grindiest of Cardinal hitters, both this season and in the past.

Luckily for us, we don't have to rely on narrative to see if Randal Grichuk is chasing fewer pitches out of the zone; we have numbers for that. The following figures come courtesy of FanGraphs' Pitchf/x plate discipline numbers.

In 2014, Grichuk's O-Swing%, which measures the percentage of balls outside the strike zone a hitter swings at, was 35.7%. That means that Randal Grichuk swung at more than one out of every three balls he saw in 2014. . Certainly seems like an area ripe for improvement, right?

Well, after going home and working on commanding the strike zone over the offseason, Randal Grichuk in 2015 has improved his O-Swing rate to....36.3%. Which, yes, means he is actually swinging at more pitches outside the zone this year, rather than fewer. Not a whole lot more, mind you, but more. At the very least, he hasn't improved in this area.

But maybe he's increased his plate coverage, you say! Perhaps, as this narrative goes, Grichuk's contact ability is improving, and he's able to make contact with those balls outside the zone, which would go a long way toward excusing his tendency to expand the zone.

Nope. In 2014, Grichuk made contact on 62.1% of the swings he took at balls outside the zone. This season, that number has fallen all the way to 52.3%. So he's swinging at more balls, and making contact with fewer of them. Neither of those things says to me this is a player who has improved anything at all about his plate discipline, nor his ability to cover-slash-command the plate.

Now, I will say this: there is a positive trend in Grichuk's numbers, which is found in O-Swing's complementary piece, Z-Swing%. Z-Swing percentage is, given the context, exactly what you probably think it is, which is the percentage of pitches inside the strike zone that a hitter swings at. It doesn't tell us much about how good or how bad those strikes were to hit, necessarily; a dick-high batting-practice fastball is no different from a painted changeup at the knees on the corner in this measure. So, not the most detailed of brushes, but still.

In 2014, Grichuk swung at 69.1% of the strikes he saw, which is, as you might expect, a fairy aggressive number. Not hugely so; for comparison's sake, Matt Holliday has attacked a remarkable 77.7% of the strikes he's been thrown this season. Now, that's significantly higher than Holliday's career rates, but the example is made to illustrate you can succeed while swinging at an even higher percent of strikes than what Randal has this year.

His Z-Swing% in 2015 is nearly identical, at 69.8%. So, really, we have a player who swings at slightly more strikes and slightly more balls this year than last, but with both number being close enough we could chalk up the difference to random fluctuation. My point is this: Randal Grichuk is not, in any way, shape, or form, a meaningfully more patient, disciplined hitter this year.

However, I did say there was a positive in the numbers, and that positive is this: Grichuk's Z-Contact rate, which measures the percentage of swings at strikes upon which he made contact, has increased this season by a fair amount, from 75.9% to 80.7%. That's obviously a good thing; Grichuk is swinging and coming up empty less often in the strike zone, even if the total number of balls and strikes he's swinging at hasn't significantly changed.

Overall, Grichuk is swinging at virtually the same number of pitches he did last season; his total Swing% has increased from 51.1% in 2014 to 51.8% this year. He's also seeing a nearly identical number of pitches in the strike zone. In other words, the way he's being pitched hasn't changed any, and he hasn't actually improved his command of the strike zone whatsoever. He's swinging at just as many bad pitches as he did last year, and actually missing them more often. So the narrative of the uber-talented young slugger who goes home over the winter and works hard to improve his mastery of the zone is bunko.

One interesting aspect of this, however, is the fact that Grichuk's worse contact rate on pitches outside the zone may actually be helping him. After all, making contact with a pitch ankle-high and outside is rarely going to lead to a positive outcome; it's possible that, by swinging and missing on more of those pitches, rather than making weak contact, Grichuk's overall outcomes have improved because he's doing a worse job getting the bat on the ball. It may seem paradoxical, but when you consider that a swing and miss at a ball is a strike, and there's really only something like a 1:3 chance that strike constitutes an out, while a weak grounder hit on a ball well off the plate can constitute an out the vast majority of the time, there's an argument to be made that missing a ball entirely, giving the hitter another shot at a potentially more hittable pitch, is a preferable result to putting the ball in play. The fact we see Grichuk's walk rate up somewhat this year while he swings at more pitches overall would also seem to argue for the swing and miss being better than a weakly hit ball.

Still, the fact remains that the narrative of Grichuk having improved his knowledge of the strike zone, of him taking fewer bad swings at bad pitches, is patently false. If anything, his plate discipline this year is actually worse, rather than better. His plate coverage appears to be worse, also. Which, as I said, might paradoxically be getting him better pitches to hit, in a weird sort of way.

It's sort of amazing what a batting average on balls in play of .372 and a HR/FB% nearly 2.5 times as high this year as it was in 2014 can make people think about a hitter, isn't it?