Did you know it's too early to read much into baseball statistics? It's true! And I'll remind you every day until June, when I'll remind you every other day. Brandon Belt's early defensive stats are awful, but that's probably sample size. Trevor Brown would be a first-ballot Hall of Famer if he kept hitting like this, but that's probably sample size. I'm actually sponsored by Sample Size Energy Drinks, and I get $50 for every use of the words "sample size." Sample size!
Except the Giants' starting position players are all creeping up on 100 plate appearances. And it turns out there are stats that stabilize around this milestone. From Russell Carleton's seminal study almost a decade ago:
The following are the stats that were stable enough (correlation > .70) at each plateau to be considered reliable. Again, these are the PA levels at which each stat can be considered to be saying something about an individual player.
50 PA – swing percentage
100 PA – contact rate, response bias (both just missed at 50… the real number is probably around 70)
Response bias is the decision to swing or not swing (PDF) when a pitch is on the borderline, but we'll focus on swing percentage and contact rate and see if there are any nuggets of wisdom we can glean from Giants hitters in the early part of the season.
Here's how often they've been swinging:
|Hitter||2015 swing %||2016 swing %||Change|
See? Those stats are pretty stable, alright. The Giants' propensity to swing or not is almost identical to last year. Now, it's important to note that swinging more doesn't have to be a bad thing. There are hitters out there who are overly passive and constantly getting into poor hitter's counts.
But Hunter Pence's numbers probably mean something by now. If I had to guess, it's that he's been offered slop and more slop, as if there were a league-wide scouting consensus. Throw him breaking balls down and away, over and over again. It's where a third of the pitches thrown to him went last year. It's a similar percentage this year, but he's swinging at them far less.
It takes about 200 plate appearances for BB rate to stabilize, but the gains in Pence's swing percentage are showing up right where you think they would: He's on pace to blow away his career-best walk rate, walking 12.2 percent of the time, compared to a career average of 7.4 percent.
Now to the contact rate:
|Hitter||2015 contact rate||2016 contact rate||Change|
Have you noticed that Brandon Belt is making more contact this year? I suspected as much, but here's the limited-sample-but-still-useful proof. None of the other numbers are striking, but Belt is fouling off more pitches and making more contact. More pitches fouled off means more close pitches to take. And you know Belt will take them, occasionally at his own peril. It's working out for him this year.
He's halved his strikeout rate, while boosting his walk rate by five percent. Which are both excellent signs. This would be a lower strikeout rate for him than he had when he was destroying the Cal League. It's still early to read anything into that, but strikeout rates stabilize around 150 plate appearances. He's getting close.
There isn't a perfect way to look for response rate, so we'll use percentage of swings on pitches outside of the strike zone:
|Hitter||2015 O-swing %||2016 O-swing %||Change|
And there are our two heroes, being outliers again. (Along with Brandon Crawford, which I wasn't expecting, so keep an eye on that.)
Hunter Pence is swinging at fewer pitches, and he's also swinging at fewer pitches out of the strike zone. Brandon Belt is walking more than he's striking out, primarily because he's making better contact and swinging at less slop. The sample-size caveat still applies, but when you're talking about these specific stats, you don't have to be quite as skeptical. There's a chance that two of the most important Giants hitters have altered their approach for the better this season.
I'll take that chance.