One of the problems with the Mike Trouts and the Bryce Harpers of the world – the only problem with them, I assume – is that they've raised our expectations for young players. Players such as David Ortiz and Jose Bautista take time to realize their potential. Sometimes, a player who excels in the minors will experience growing pains at the major-league level. An inauspicious beginning to a player's career doesn't necessarily doom him forever.
Then again, there's inauspicious... and there's awful. Through his first two seasons, Tigers third baseman Nick Castellanos was awful. Among 117 position players with at least 1,000 plate appearances, he had the fourth-worst fWAR (-0.6) and the third-worst rWAR (-0.9). As a former top prospect – whose background we'll discuss shortly – he clearly possesses talent, but he's yet to display it at the major-league level.
Castellanos struggled a bit on offense, with a 94 wRC+ over his 1,192 plate appearances in those years. In November, Eno Sarris broke down the changes Castellanos has made with the bat; I'd check out that article to learn more about that aspect of his game. Right now, I want to zoom in on the other side of the ball, where Castellanos flopped completely. From 2014, when he slotted in as the Tigers' regular third baseman, through 2015, he cost his team 39 runs according to DRS and 28.7 runs according to UZR. Each of those ranked as the worst among all qualified defenders.
The Tigers wouldn't want defense of this caliber from any player — but from a player who just turned 24, it's pretty scary. Theoretically, fielding peaks pretty early:
That graph comes from BtBS alumnus Jeff Zimmerman, who researched aging curves here in 2011. For most position players, defense improves in the early 20s, then plateaus, then steadily declines. In other words, Castellanos might have nowhere to go but down.
Does this represent his true talent level? Let's look at some scouting reports from Baseball Prospectus. Castellanos debuted in 2010, and while Kevin Goldstein clearly liked him overall, he deemed his glove his worst tool and called him a "merely average defender" at third base. By 2011, however, things had gotten a little better in Goldstein's view:
He's improving at third base to the point where scouts think he can stay there, and a plus arm helps his cause....Castellanos still has a long way to go defensively, but he has the tools and simply needs to improve his footwork and fundamentals.
The signing of Prince Fielder before the 2012 season moved Miguel Cabrera to third base, which in turn made Castellanos transition to the outfield. There, his forecast didn't improve by much. Jason Parks wrote after 2012 that he hadn't adequately learned how to read and track balls, which negated his strong arm and made him an "average at best" defender. Parks didn't see much progress in 2013: after the year, he posited that Castellanos had a "below-average profile in [the] outfield corner," and that he was "unlikely to play solid-average at third."
After 2013, two things happened: the Tigers traded Fielder to the Rangers, and they called up Castellanos permanently. With first base vacant for Cabrera, that allowed Castellanos to move back to the hot corner. Perhaps the time away from his natural position prevented him from working on those "fundamentals" that Goldstein cited. Or maybe Castellanos's defensive ceiling – as reflected in Parks' writing – is mediocrity, and his floor is, well, the atrocities that he's accomplished so far.
So what should we expect for 2016? On the one hand, if what we saw from him in the prior two seasons represented his nadir, he should take a step forward this year, as his production regresses toward the mean. On the other hand, that logic might not apply to fielders this terrible. To resolve the issue, let's drink from the analytical Holy Grail: the Play Index. Our search will cover players in the last half-century who cost their teams at least 20 defensive runs before their 24th birthday. We'll then look ahead to the remainders of their careers, to see how they aged from there.
Take a look at the mostly uninspiring result of those labors:
|Player||Pre-24 PA||Pre-24 Rfield||Pre-24 Rfield/600||Post-24 PA||Post-24 Rfield||Post-24 Rfield/600|
Cano is the biggest reason for optimism here. After butchering second base in his first major-league exposure to the position, he's developed nicely and become a solid player in the field. We can't just pick out the most appetizing cherry, though – we need to evaluate all the fruit. On the whole, this group didn't advance that much beyond their early futility. They averaged -12.8 defensive runs per 600 plate appearances before age 24, and -5.3 runs/600 thereafter. Positive regression can only do so much; it won't mask a player's deficiencies forever, as these men illustrate.
Many of these players shared another trait: solid offense. On average, they earned 11.4 batting runs per 600 plate appearances from age 24 onward. That explains why they received so much playing time despite such poor defense – they averaged 4,171 plate appearances in the later part of their careers. Castellanos's hitting carried him through the minors, and if he can reach his potential at the plate, it could help to compensate for his defense.
We obviously don't know what direction Castellanos will head in. He could recover, as Cano did, or he could continue his plummet, as Cano's former teammate Derek Jeter did. The Tigers would be happy with the middle, subpar-yet-respectable defensive ground – which still doesn't leave that much hope for Castellanos, especially as he moves into his mid-20s. The Tigers better pray that his bat comes around, because the future doesn't appear too sunny for his glove.
. . .