Having proposed the thought experiment and sought out your answers, it's only fair that I answer myself. With a hopefully riveting offseason just days from kicking off in earnest and with Joe Maddon already in the fold, let's pound out the hypothetical stuff in advance of dissecting the real moves.
It's not that answering this question is easy; it's not. It's merely that this is something I've thought about extensively from the moment I saw Addison Russell's name as the primary return for Jeff Samardzija. The Cubs have three plus shortstops, two at the major-league level and one rapidly approaching. Something has to give, be it as a position switch or a trade.
You all made your preference quite clear in the poll. As of Saturday morning, there were 2,747 votes in the poll in my original post on this topic. 60 percent voted for Javier Baez, 22 percent for Starlin Castro and 18 percent for Russell.
So let's move on to my answer.
I'll start with the youngest player: simply put, I think Addison Russell is going to be a superstar.
This paragraph will be the epitome of prospect love, so prospect skeptics or haters beware. Russell's entire offensive game is plus. Russell has the hands and the approach to hit .300 in the majors. He has the bat speed and the physical strength for plenty of 20-homer seasons with 25 homers looking possible on a regular basis; he muscled out 12 home runs in just 50 Double-A games after coming to the Cubs last summer, so some power is there. Russell has also shown an advanced approach in the minors: although he walked in just 6.5 percent of his plate appearances this year, that tally was 12.1 percent as a teenager at High-A the year before. Russell looks like the kind of guy who can post .290/.350/.480 lines on a regular basis with the chance for even more on-base and power production. That alone probably isn't enough to push Russell over the top given his injury and developmental risks.
His glove is. Russell's actions in the field are smooth and natural in a way that Castro's rarely are. Russell's arm lags behind that of Baez, but it's at least on par with Castro's. Given slightly better range and a noticeably better glove, Russell figures to be the best defensive shortstop among this trio, even if he struggles upon his promotion to Chicago. I'm willing to wait another year or two for Russell's game to blossom given the immensity of his ceiling.
This leaves me choosing between Castro and Baez.
I think that Castro is a very good player. I really do. Castro is already a well-established average regular shortstop, and he has shown flashes of more. He has grown into additional power as he reaches his mid-20s, and his walk rates have inched upward as well. Castro consistently grades just a tick below average with the glove at short; however, that's high praise as a legitimate big-league shortstop glove is an enormously important asset. He's a core piece for a team that is increasingly built to win both now and throughout his prime. This is not lost on me. Castro figures to have something like a decade's worth of three or four WAR seasons in front of him.
Moving on to Baez, this decision is simultaneously simple and brutally difficult. With the glove, the pair are comparable in terms of overall defensive value. Baez has a massive arm compared to Castro's solid one, but Castro is much more consistent in the field, despite Baez's strides in that regard. Defensively, they likely produce similar value while taking different paths to get there.
So this battle comes down to the bats. We all have a good idea of what we have with Castro: steady, high-average, average on-base ability, and some emerging power. .290/.345/.450 lines from a shortstop are really strong, and Starlin is nearly at that level already.
Baez is the great unknown. As we have all mentioned countless times, Baez is either going to compete for MVP awards or he's going to fight for a roster spot. It's nearly impossible to rely on such a player until you know what you have, a situation we won't find ourselves in until Baez has 1,000 or so plate appearances under his belt.
But given the construction of the roster, I think it's a risk worth taking. With Russell, Arismendy Alcantara, and Albert Almora all hanging around to complement Baez, I'm confident that the Cubs can cover second base, shortstop, and center field. Offensively, the team already has a key piece in Anthony Rizzo. At the same time, Jorge Soler, Kris Bryant, and Kyle Schwarber are all nearing the opportunity to establish themselves as impact bats. The lineup should be able to handle the loss of a solid bat for the shot at another massive one.
Baez is that massive bat if it comes together, just like it has at every level thus far. I can still see Baez getting to .275/.340/.540 lines repeatedly, even with a higher-than-average strikeout rate. There's so much power in the bat. While I fully acknowledge that he looked horrendous during his stint in Chicago last year, the guy can hit. He has hit at every level. The power will buy him some time -- he just posted a .155 ISO in the Majors as a 21-year-old and we were all disappointed -- and I think he figures out how to hit enough to emerge as the impact bat many of us hope he will be.
Regardless, it's worth the shot that Baez becomes a superstar to convert Castro into a young pitcher or two via trade should the opportunity present itself.
If Baez flames out and Castro is traded, leaving us with only Russell, I'll be saddened like many of us. At this point in time, however, I'm fine trading the "sure thing" in Starlin for the shot at glory that Baez represents.