When you think about plate discipline — specifically good plate discipline — what comes to mind? Sabermetricians fall into two broad schools of thought on what defines the term. On the one hand, some will look at how well a player can detect the difference between a ball and a strike. On the other hand, some will judge a player based on his ability to make contact when he swings. We have metrics for each of these; O-Swing and Z-Swing rates gauge the former, while swing and contact rates (and the resultant whiff rate) keep track of the latter. Still, the fundamental debate remains, and I don’t expect it to cease any time soon.
I’m not entirely sure which camp I fall into. Instead of ruminating on that, I’d rather look at the players who cross over between the two — the ones who have noteworthy plate discipline in the view of one group, and cringeworthy plate discipline in the view of the other. The Brewers, for the time being, have two such players: Chris Carter and Keon Broxton. Each of them possesses a great batting eye when it comes to balls and strikes…as well as not-so-great judgment when it comes to making contact.
Take a look at their 2016 production in the aforementioned metrics, along with a comparison to the major-league baseline:
As is standard for plus stats, 100 is average, and each tick above or below that is one percentage point above or below average. Also, none of these metrics are park-adjusted. Park factors are hard.
Both Carter and Broxton lay off most of the stuff they see outside the strike zone, and in doing so, they don’t become passive within the strike zone. But when they decide to take a cut, they’ll come up empty disturbingly often. The question is, can the former ability negate the latter?
In a poor attempt to answer that, let’s look at some similar players. We’ll set our thresholds at:
- O-Swing+ of 90 or below
- Z-Swing+ of 100 or above
- Whiff+ of 130 or above
How many qualified campaigns, since 2008 — when PITCHf/x data became reliable — can meet those criteria? In addition to Carter’s current one, just 23:
|2010||Melvin Upton Jr.||25.0%||88||64.0%||104||12.0%||138|
From here, we’ll look at a few different era-adjusted metrics. One obvious question arises, based on the parameters of this study: How did these players fare in terms of strikeouts and walks?
|2010||Melvin Upton Jr.||11.0%||129||26.9%||145|
In general, not too terribly. Except for A-Rod last year and Corey Hart — remember that guy? — in 2011, they all went down on strikes at a clip 20 percent worse than average. They compensated for that, though, with a boatload of free passes: Only five of them weren’t at least 20 percent better than average in that regard. On average, these players notched a 157 adjusted walk rate and a 149 adjusted strikeout rate; in other words, their on-base ability made the lack of contact stomachable.
What about when they put the ball in play? Did all of those whiffs bring weak contact, or did their pitch recognition allow them to see meatballs coming and pounce?
|2010||Melvin Upton Jr.||.187||129||.304||102|
The latter theory holds true, and it’s not especially close. In terms of BABIP, the results are a mixed bag — Pena repeatedly struggled to get hits, while Stubbs never stopped racking them up — but overall, this group was just three percent worse than average in that regard. And evidently, they swung-and-missed so often because they were aiming for the fences: These sluggers averaged a 144 adjusted ISO. In the end, that patience seemed to pay off.
And the final, most salient question: How well did these players perform as a whole?
|2010||Melvin Upton Jr.||107|
Not too shabbily! They averaged a 113 wRC+, and only five of them had a subpar batting line. In the end, it doesn’t seem to matter if you whiff a ton — so long as you can make up for that with a discerning eye. For Carter and Broxton, this seems to be welcome news.
Now, a couple of massive differences do exist between Carter and Broxton, chief among them being speed. The former plays at first base, and he’s not the Anthony Rizzo breed, either: In his career, his baserunning has been worth -10.5 runs, per BP’s data. The latter, by contrast, covers a ton of ground in center — and on the basepaths, where he earned 1.3 runs in just 244 plate appearances this year. That speed translates to hitting, too, as Broxton can leg out infield hits and take extra bases more readily than Carter.
This distinction, and the results of the study, can help us to establish a rough floor for both players. I’d imagine that, if Broxton maintains this plate discipline, he shouldn’t fare any worse than Stubbs’s 2011 season. During that year, the Reds outfielder put up a wRC+ of 90 — the lowest in this sample — and accrued 1.8 WARP over 681 plate appearances. For Carter, he’d probably bottom out around Reynolds’s 2010, when the nominal third baseman earned 2.4 WARP in 596 plate appearances despite a 96 wRC+.
Of course, the other difference is that Carter has a lot of experience — and he has bottomed out before. He came to the Brewers this season when the Astros non-tendered him, following a 104-wRC+, 0.4-WARP 2015 campaign. If he regresses to that again, he won’t have much value. Broxton, though, just surpassed the rookie limits this year, meaning the sky remains the limit (in theory). Who knows? Maybe he’ll cut down on the swings-and-misses, retain the selective swings, continue clobbering the ball when he makes contact, and become a star. Even if he doesn’t accomplish that, we’ve seen that this approach won’t doom him.
All data as of Thursday, September 22nd.