Philadelphia Phillies
The Philadelphia Phillies would be another example of a contending team that would be trading for Carlson to backfill after injuries and underperformance. The Phillies demoted Johan Rojas in June but recalled him just last week. When Rojas hasn't been in Philly, Brandon Marsh has been filling in as a replacement center fielder. Marsh is a good center fielder, but his move to the middle has pushed David Dahl to a starting spot, and Dahl is a below-average outfielder on the defensive side of the game.
The Phillies also boast another former top prospect in Christian Pache in the outfield, but he has never been able to put it together at the biggest stage in baseball. Rojas's offensive profile is a near equivalent to Carlson's with a slash line of .234/.273/.298, so it's feasible that Carlson supplants Johan Rojas in the starting lineup.
Regardless of how the Phillies choose to use Carlson, he will provide depth for an outfield that could use some defensive help. The Phillies are also without key starters in Bryce Harper, Kyle Schwarber, and J.T. Realmuto, so reinforcements of any kind are welcome in Philly. Carlson is a buy-low candidate for the Phillies.
The Cardinals could go a couple of routes when asking for players in return. They could swap two struggling players in Carlson and Pache, but the Cardinals may not be interested in that deal, especially considering Pache's crazy strikeout numbers and lack of power. The Cardinals could also dip into the Phillies' prospect pool and land someone like Griff McGarry (#10 according to MLB.com), or even Mick Abel (#5 according to MLB.com) if Carlson is packaged with a prospect. Abel has struggled this year, though, so a one-for-one deal could be had.