Miami Marlins
The Cardinals and Marlins have been linked as trade partners for at least two years now. The Marlins have ample starting pitching both in the majors and the minors, and the Cardinals have ample depth players in the field. A swap of strengths has seemed inevitable for a while now. Miami averages 4.17 runs per game this season, so an offensive upgrade is necessary as they continue their push for the postseason.
The Marlins currently employ Bryan De La Cruz, Jesus Sanchez, and Dane Myers in the outfield. Once Jazz Chisholm returns from injury, it is presumed that he will return to center field for the team. Jorge Soler also figures to fill in time in the outfield when he isn't in the DH spot.
While Carlson won't play every game in the outfield for the Marlins, he stands to be a strong platoon player for them and a fourth outfielder who can come in and play strong defense for them (only Jesus Sanchez has a positive defensive runs saved number). He also provides certainty in future years, as Soler is a free agent after next year.
Prediction: Dylan Carlson to the Marlins, Jesus Luzardo to the Cardinals