It’s tempting to reflect back on just how fantastic Nicholas Castellanos was as a Cub, especially after hearing that there is “mutual interest” in working out a deal to extend that relationship. In 225 plate appearances following his trade from Detroit, the high-energy outfielder slashed .321/.356/.646 with 16 home runs and 21 doubles, quickly becoming a fan favorite.
In a vacuum, that’s certainly the kind of player the Cubs or any other team would be thrilled to have as a part of their roster. But even though the Cubs sucked out loud at times last season, Wrigley Field isn’t a Dyson. As such, the case for retaining Castellanos is a complicated one.
The bat stands out as the primary reason the Cubs would want to retain Castellanos, but he isn’t exactly an easy player to project offensively. Thanks in large part to a hyper-aggressive approach that has been a consistent hallmark of his offensive profile, Castellanos has relied almost exclusively on batting average as the foundation of his offensive output.
So what, you might say. You need look no further than Javier Báez for an example of a highly successful player who foregoes walks in favor of an offensive gameplan that’s built almost entirely on delivering a high volume of hits. There’s a key difference between Báez and Castellanos though, and that is power.
Javy’s prodigious pop helps make his game a little more sustainable because there’s significant reason to think that when he makes contact, he’s going to put a charge in the ball. His isolated slugging percentages of .264 and .250 over the last two years are reflective of his ability to produce offensively even with an offensive profile that is so batted ball dependent.
Despite a late-season surge that saw him more than double his home run total, Castellanos doesn’t have that power profile. His staggering .325 ISO down the stretch belies a relative lack of power that had previously been a weakness in his game. He was producing a relatively anemic .189 ISO prior to his acquisition from Detroit, a step back from outputs of .218 and .202 in the two previous seasons.
So the real question the Cubs need to answer is whether Castellanos has genuinely taken a step forward and can maintain that high level of production moving forward. It’s far from a slam dunk, and it’s not unreasonable to harbor concerns about how a player like him projects in the medium- and long-term. Because his game is dependent almost entirely on balls in play finding safe landing spots, there are two major pitfalls for Castellanos that could seriously neuter his offensive output.
As with all players, the rate at which his batted balls become hits is based in part on quality of contact. But luck is a factor as well, so players like Castellanos who don’t draw many walks are always at risk of being bitten by poor BABIP luck. Combined with the inability to project his power and there is reason for pause. Even quality contact ca, result in outs, and Castellanos profiles as someone who is more at risk of that happening than others.
Then there’s the reality that, even though Castellanos is only entering his age-28 season in 2020, he’s going to have combat declining bat speed at some point. Players with his offensive profile have very little else to rely on once bat speed falls, so even marginal drops in the rate or quality of his contact could quickly turn him into a significantly less productive offensive contributor.
These concerns about Castellanos’ vulnerability to poor batted-ball luck and potential for a steep decline don’t even touch on what is by far the worst part of his game: Poor defense. I’ll spare you a deep dive here because that deficiency has been written about extensively, but Castellanos has often profiled as a genuinely poor defender and there’s not any reason to think that will change as he gets older.
Given the realities of the Cubs pitching staff’s low strikeout rates, they’re more dependent than most rotations on having the defenders behind them convert batted balls into outs. An outfield that already has an adequate but unspectacular Kyle Schwarber in left field and what would be a playing-out-of-position Jason Heyward in center won’t do its pitchers many favors. Even though playing at Wrigley mitigates some of the pitfalls of Comerica’s more spacious confines, Castellanos will be in the passable category at best.
Between these on-field factors and what is looking like another winter with limited payroll flexibility, there are plenty of reasons to question just how good a fit Castellanos is for this version of the Cubs. While his offensive explosion and infectious energy make him a tempting target to re-sign, there are ample reasons to proceed with caution.