When you look at the list of the top third basemen by WAR this season, there are definitely some funny names. Manny Machado, Matt Carpenter, Josh Donaldson and Todd Frazier make up 50 percent of the top eight. Of course, it’s early in the season, and the likelihood that Machado stays on pace for an 9.0-WAR season is about the same likelihood as our very own Casey does the same. That is to say, it’s not likely.
I bring up third basemen and their expectations because nestled right up there between Evan Longoria and Carpenter is our very own Kyle Seager, who has recorded 1.3 fWAR to this point and slashed an impressive .293/.348/.496. It’s not hard to replace Chone Figgins and subsequently be considered a demi-god, but Seager has gone beyond just replacing Figgins and has surpassed even the optimistic expectations. It’s fair to ask now, how much should we expect going forward?
Seager has already surprised us, and he could definitely continue to do so. I proceed with caution.
Starting out critically and skeptically, the first place anyone (anyone?) goes to look for impending regression to the mean is the BABIP stat. Seager’s .340 BABIP this year should evoke suspicion. Before this season, his career BABIP in 852 PA was under .300, and the major-league average is also just under .300. Additionally, with a decreased line drive rate and increased popup rate, we have many reasons to believe Seager’s BABIP is on its way down, and with it everything else.
But maybe not down all the way down.
In each of Seager’s three major league seasons, we have seen improvement in his plate discipline. Back in 2011, he used to chase balls outside the zone at the league average clip—swinging at about 30 percent of all balls—which isn’t half bad for a rookie. Now in the 2013, he’s dropped that chase rate even further, down to 23.4 percent. The immediate question is, is that significant? Will it stick?
We know that plate discipline numbers stabilize about as quickly as anything we use to measure hitters. If you’ve taken a stats class, you might be thinking about using the binomial distribution to test for a significant difference. That’s a good place to start. But Fisher’s exact test gives a p-value of 12 percent, and that leaves us with some doubt as to whether or not Seager has actually improved his chase rates (not to even mention that the assumptions required for such a test are violated in baseball).
To find something significant, I will focus on overall swing rate—mostly because it has a larger sample size. The same test gives us a p-value of virtually zero percent for overall swing rate. That implies a lot of evidence to suggest that his “batting eye” and approach have changed, that something real has changed and will stick. Okay, so let’s go with that. He’s swinging less overall, and that has correlated with an improved walk rate. I like that.
However, the reduced overall swing rate is also a product of Seager swinging less at balls inside the strikezone. While chasing pitching outside the zone is rarely—if ever—a good thing for a hitter, what about holding back on strikes? We can’t complain about Seager’s contact results this year, as he’s on pace for a .293 average, about 20 homeruns, and 55 doubles. But what about others that have made similar changes…have they experienced boosts to overall success?
Since the PITCHfx era began in 2007, only five players have been able to maintain a swing rate 10 percent lower than the previous season. That suggests that Seager’s 9.7 percent swing reduction might be hard to maintain, so let’s isolate the players that were A) able to reduce their swing rates by at least 5.0 percent down to something in the 30’s and B) made contact better than 80 percent of the time. These players are a lot like Seager in terms of swinging and contact.
As you can see, each of these 12 players (prior to Seager) reduced his swing rate by at least 5.0 percent. And then, subsequently the next season, 11 of the 12 were able to “keep some of it off.” In other words, almost all of them regressed some, but only one regressed all the way back to his relatively gluttonous swinging ways.
Perhaps more interestingly, this is the improvement (or decline) that each player saw during the reduced swing rate:
Almost without fail, the players increased their walk rates, but the overall batting lines were a little more scattered. While the 13 players including Seager increased their average wRC+ by nearly 10 points, nearly half actually declined. In other words, due to other changes in things like BABIP and power, improved offensive value was not guaranteed for these players. The average in this case may not be the best indicator, but at least it’s positive.
Seager has contributed improved offensive value to this point, and though I can’t say there’s any guarantee he’ll maintain that, I am confident saying that his walk rate should stay up in the 8.0 percent range. A lot of other players on that list improved even more than Seager has this season, so there is enough precedence to believe that Seager’s changes will not only stick, but that they could continue to contribute improved offensive value.