Don't get me wrong, the St. Louis Cardinals' free fall from power in the NL Central and the Milwaukee Brewers' rise to prominence can not, and should not, be defined by one trade, but I do think the blockbuster moves these division rivals made sent them on completely different trajectories.
Following the 2017 season, the Cardinals had their eyes set on acquiring an outfielder who could be a middle-of-the-order bat for their lineup. The Miami Marlins happened to have three they were looking to cash in on.
The Cardinals swung a deal for the biggest fish of the bunch, agreeing to acquire Giancarlo Stanton before he declined to waive his no-trade clause.