24 April 2015

Microtrends: Caleb Joseph's Plate Discipline

Continuing my series from last week (would we call this a microtrend?), I've decided to look into another interesting facet of Baltimore's season. Although the year is still quite young, the changes we note may last for its duration — and that may occur with Caleb Joseph's offensive performance.

Joseph posted an altogether successful rookie campaign in 2014, mainly because of his strong defense: He threw out 23 of 57 attempted base stealers, and acquired 84 extra strikes via framing. Sadly, hardships at the plate accompanied his excellence behind it, as he posted an offensive line 28% worse than the major-league average. A low average on balls in play had a hand in his struggles, but plate discipline bears most of the blame for them; he struck out in 25.1% of his plate appearances, while only walking in 6.2%.

While the ability to hit the ball can come and go, the ability to see it generally doesn't change. In other words, players will see some BABIP and ISO fluctuation from year to year, but their BB% and K% will remain pretty stable. Thus, we should probably look at Caleb Joseph's 14.9% walk rate and 19.1% strikeout rate for 2015 with a bit of skepticism. Nevertheless, they may not decline to the degree that we'd expect, if we can believe his peripherals.

One thing we can say about Joseph, with some amount of certainty: He swings less now. Swing rate stabilizes at 50 plate appearances, and Joseph's 47 trips to the dish comes pretty close to fulfilling that requirement. In that span, he's offered at 38.9% of the pitches he's seen, much lower than last year's 46.8% mark. That patience hasn't come equally — his O-Swing% has plummeted from 21.2% to 30.6%, while his Z-Swing% hasn't dropped much at all (62.6% to 60.5%). The early nature of the season notwithstanding, Joseph, appears to have adopted a more disciplined approach.

It's worth noting that Joseph hasn't done more with the cuts he's taken. At 78.6%, his contact rate hasn't shifted much from 2014's 79.5% figure. With that said, his newfound composure means he's decreased his swinging strikes; whereas last year, he whiffed at 9.6% of the pitches he saw, this year pitchers have fooled him 8.3% of the time. Additionally, he's seen fewer pitches in the strike zone, which doubly compounds his aforementioned composure: He takes fewer looking strikes, and more balls. So far in 2015, 17.8% of the pitches he's taken have (theoretically*) been looking strikes, down from 18.9% last year; additionally, 43.3% of them haven't (theoretically*) been strikes, a notable decline from 34.4% prior.

*If we had robot umps already, we wouldn't have to deal with theory.

To go down on strikes, a batter must have at least one of the looking or swinging variety, and Joseph has made it so that he doesn't do those as often. To take a free pass, a batter must take four pitches out of the strike zone, and Joseph has made it so that he does those much more often. Put it together, and you get an all-around better approach at the plate, and one that might bring Joseph sustained playing time at the major-league level.

For Joseph, a lot of this year's offensive improvements will probably dissipate when the sample size grows. (If he owns a .414 BABIP by season's end, I'll quit baseball writing forever.) As his average goes down, pitchers will pound the zone more against him; he'll begin to press, and in doing so will sacrifice some of the gains he's made so far. But expecting him to regress to 2014's level, when he's done all of this so far, may prove foolish if he keeps it up.

1 comment:

Matt Perez said...

Interesting article. What your data show though is that Joseph swung less during a significantly large sample. But that doesn't mean he swing less now. It means that he didn't swing as much as he has previously over a meaningfully large sample size.

Basically, to quote Carleton, we can say this:

"For example, last week I found that strikeout rate stabilized around 60 PA (using something a little different—and better—than split-half, but functionally for now, it's the same idea). That is, Player X's strikeout rate after 60 PA was (past tense) a reasonable reflection of his true talent during that timeframe. Whether or not the first 60 PA of a season predict anything about the next 500 is an entirely different question, with a somewhat different answer."


What does this mean? Basically, Joseph swung less over a large sample and that could have an impact on next year and it's worth keeping an eye on in the future.