OF Alek Thomas, Arizona Diamondbacks
The idea of another outfielder is probably controversial amongst fans. Some would argue that the Cardinals already have plenty, while others would say they need to quit putting "infielders in the outfield". Regardless of what we think, it's clear that outside of Jordan Walker and Lars Nootbaar, there isn't much trust for their other traditional outfield options.
Specifically, the team seems to believe they lack a true center fielder outside of Tommy Edman. Sure, they'll play Nootbaar or Carlson out there when they need to, but it doesn't seem like they truly see either as a center fielder.
Enter Alek Thomas, who after getting demoted to Triple-A earlier this year, has been on fire for the Diamondbacks as of late. Thomas is slashing defensively. He hits left-handed, is a former top prospect, and is just 23 years old, making him a very intriguing target for St. Louis long term.
Arizona is capable of making a deep playoff run this year, and they'd be wise to try. The Dodgers will likely be a juggernaut once again next season, the Padres are having a down year but are sure to aggressively retool, and the Giants are always going to be lurking.
The Diamondbacks need more pitching, so I could see them targeting a Jordan Montgomery and possibly Jordan Hicks in a package that features Thomas, or possibly even just a straight swap for Montgomery. This would improve Arizona's pitching staff greatly, and still leave them with good outfielders at the Major League level and top prospect Druw Jones developing in the minors.