Keith Law has the Cubs as the 2nd most improved farm system of 2021...
Chicago Cubs (pre-2021 ranking: No. 26)
The Cubs traded everyone, or just about, and acquired a set of prospects who, taken as a whole, bring a strong balance of probability and long-term upside, adding a needed infusion to a system that was down after years of low draft picks and trades. They added center-field prospect Pete Crow-Armstrong, a first-rounder last year and a top-100 prospect coming into 2021, for Javier Báez; Crow-Armstrong is out for the year after surgery on his non-throwing shoulder, but his outlook as a potential leadoff hitter with plus defense remains intact. They picked up a pair of upside players for Anthony Rizzo, getting center fielder Kevin Alcantara, just 18 and now hitting .365/.443/.577 in 61 plate appearances between the two complex leagues; and a real lottery ticket in hard-throwing Alexander Vizcaino, who has been ineffective in the brief time he’s pitched this year after missing two months due to injury. And they got power-hitting corner outfielder Alexander Canario, who has four homers in nine games since the trade, plus command right-hander Caleb Kilian, a potential mid-rotation starter, for Kris Bryant. They even landed a prospect for extra outfielder Jake Marisnick, getting right-hander Anderson Espinoza, a two-time Tommy John surgery recipient who’ll probably move to the bullpen but work with two plus pitches there.
The Cubs had a solid draft, getting a low-ceiling but high-probability starter in lefty Jordan Wicks in the first round, then going for more ceiling with their next three picks, including a pair of high school hitters and then toolsy Arkansas outfielder Christian Franklin, a plus defender with power who needs swing and approach work, in the fourth round.
Meanwhile, their top prospect coming into 2021, outfielder Brennen Davis, has had a huge breakout and now sits at No. 20 on my most recent rankings, while the early returns on Reginald Preciado, acquired in the Yu Darvish trade last winter, are very promising. The Cubs came into the year in the bottom five of all farm systems, but they’ve pushed themselves up at least to the midpoint.