Here's the thing about getting old, it's kind of a drag. Sure, in most cases you have more disposable income, or at least have the extra money tied up in a (hopefully appreciating) asset. But you're probably also losing your hair, and if you're not, it's turning grey. Maybe your back hurts, maybe it's your knees, but in all likelihood, as your twenties come to a close, you've got some manner of physical nuisance that reminds you that Father Time remains undefeated, and he's not even outperforming his pythagorean record.
Andrew McCutchen is in his late twenties and probably has more of these nagging reminders than your average couch jockey does at his age. But on the field, he's been as durable as they come. He's also found himself on top of the National League MVP ballot the past four seasons, winning it in 2013 on the back of an 8.4 fWAR season that, while a distant second to Trout, was a full win above the next best National League position player, Carlos Gomez.
A lot has changed since 2013. McCutchen’s hair is obviously different (though still mostly intact and perhaps even naturally black), but so is his offensive production, which had consistently been among the league’s elites since 2012 when he broke out like a toddler with the chicken pox. McCutchen has lived by the bat, with a defense that has graded out poorly nearly every year that he's been in the league. If you're hurting your team in the field, you'd better make up for it at the plate. Unfortunately for McCutchen and the Pirates, the extent to which he's able to offset his liability in the field is diminishing.
McCutchen is 29 years old, an age where, traditionally, a player is coming off their peak, and wRC+ begins to wane, if only by single digit percentage points. But, over the past three seasons, it's been 169, 146, and now 117. Before the season, Steamer and ZiPS both projected McCutchen to put up about a .380 wOBA (incidentally, his mark from last year). So far he's managed just .343, dropping him from the Excellent/Great range to Above Average. He’s not embarrassing himself at the plate, but he’s now the third-best hitter in the Pirates' admittedly excellent outfield, and it's not even very close. Heck, even Jordy Mercer (.334) is nipping at his heels for fourth-best wOBA on the team.
"But wait," you may be saying out loud as you read this, hopefully in private, "McCutchen’s BABIP is uncharacteristically low. He’s usually comfortably above .330, and this season he’s at just .291. Regression is certain and imminent!" If you happened to be in a public venue when reading that, and in close proximity to someone who has already read this article they would agree that, yes, his BABIP is well off his career mark, but in this case, you can't use it as a verb.
Recently, Andrew Perpetua developed an expected average for balls in play (xBABIP) using exit velocity and launch angle exclusively. While he details the limitations of the statistic and ways it could be improved, the early iteration is not promising for Andrew McCutchen, putting his xBABIP at .272. This suggests that McCutchen has been lucky to reach base on as many batted balls in play as he has this season. Eeek.
And if you look at some of the stats that underpin xBABIP, it’s not difficult to see why he hasn't been BABIPing above .330 this year. He’s always hit a few more fly balls than average, but this season McCutchen is near the top of at least one leaderboard, hitting them at a 50 percent rate, 16 percentage points more than league average. Looking at his launch angle on all balls in play captured by Statcast, which is admittedly about 20 batted balls light, it’s risen from 13.4° in 2015 to 18.8° this season.
Not only is he serving up more easy outs, but McCutchen has lost a step, there's no doubt about that. At his peak, he was stealing a base 16 percent of the time he had an open bag in front of him. Then it was 12%. Then it was 8%. Then it was 5%. This year it's 4%. The legs are often the thing first to go, and McCutchen clearly doesn't have it in him any longer, which his dwindling stolen base success rate corroborates. He's also not legging out infield hits like he used to, with just one on the year so far.
So what do you do when you've lost one of the skills that made you great? You double down on one that you have left. In this case, McCutchen has focused on power. He's swatted eight home runs this year, more than a third of the way toward his Steamer and ZiPS projected total of 23 and at one of the best per plate appearance rates of his career. He's not hitting the ball harder either, at least not much, and his HR/FB rate (12.7%) isn't out of line with his career numbers. McCutchen is just playing the numbers game and giving more balls the chance to clear the fence. While it's worked so far, it's also had the unintended consequence of raising his infield fly ball rate substantially, matching his HR/FB rate and dwarfing this rate from any of his previous seasons.
And in the midst of all of this, McCutchen's plate discipline has eroded. He's walking less and striking out more than ever before. He's never had a double digit difference between the two rates; for his career, it's 5.5 percent. This season, it's more than twice that, sitting at 12.2 percent. While his approach at the plate hasn't changed dramatically -- swinging at only a few more pitches outside the zone this year -- his swinging strike rate is well above his career average.
The sum of it all has spelled a career worst year for McCutchen so far. Although his batted ball profile is yet to stabilize, it's close. And, again, it's not unexpected. The projection systems say his strikeouts and walks will move back toward his career values, and maybe they will, but they both get worse with age as well. For McCutchen to both retain the power and regain the BABIP seems to be a bridge too far. Based on the numbers, it appears McCutchen has chosen to sell out for power, and so far it's working.
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