Hi. I know it might not be what you want to hear right now, but it might be what you need--it's okay that Nick Castellanos didn't re-sign with the Cubs. It's even okay that he signed with the Cincinnati Reds. No, really.
Listen, I get that Nick is fun. His two-month (wait... he was only a Cub for two months?) tenure with our boys was filled with quotable sayings and bat spikes and dingers and doubles and all sorts of neato things that made his time in Chicago super memorable. It would've been great to have him back, yeah?
Except, maybe not? As tempting as it sounded to bring him back and stick him in RF on a daily basis, a regular outfield of Schwarber/Heyward/Castellanos is, uh, less than ideal. Schwarber has become a passable, even above average defender in LF by some metrics, but he's still not Barry Bonds out there. Heyward is a certified Gold Glove right fielder, but moving him to CF drags his defense down--in 2019, he posted a 5.3 UZR/150 in RF, but dropped to -4.4 UZR/150 in CF.
And what of Big Swingin' Nick? His defense was also not great, posting a -4.3 UZR/150 in RF for the entire 2019 season. Now, you might project Castellanos for improvement, and Mike Petriello does here, but even improvement isn't great if he's not, you know, GOOD out there--especially if you're sacrificing Heyward's Gold Glove in RF to move him to center. (That Reds OF is going to be a hot mess defensively, you guys.)
"But what about BSN's bat?!?" you might ask. Well, that's a tricky situation, isn't it? It really depends on who you believe is the real BSN. Steamer is projecting Castellanos as a 1.5 win player in 2020, posting a 112 wRC+ offensively. That's around where he's been for his career so far on average, having up and down years throughout. So honestly? It's hard to predict what he'll do in 2020. If I'm the Cubs I probably wouldn't have given him a 4 year/$64 million deal with two opt outs either, if I'm being honest. Considering his defensive fit in the OF, that's a HUGE gamble.
So what do the Cubs do now? Well, there is hope in the form of this guy:
Happ came on like a man possessed once he was back up from Iowa in 2019--so much so that he posted 1.5 fWAR in just a few short months, and a 127 wRC+--higher than the 121 wRC+ Castellanos posted on the season. And yes, I know SSS, BUT... in his CF innings in 2020, he posted a 32.2 UZR/150, which is... better than Heyward. Steamer isn't as bullish on Happ's offense for 2020, projecting him for a mere 101 wRC+, but they do project him for the same fWAR as Castellanos at 1.5, probably due to his defensive potential. So... the Cubs may already have an in-house solution in CF, and Castellanos may not drive the Reds to the top of the division the way a lot of folks think. It'll play out how it plays out, and how you feel right now depends on your belief in both players and how they did in those last two months of 2019, but I have a feeling it'll work out more okay than we might think right now.