The perennial juggernaut Astros experienced an earlier-than-expected exit from the 2023 playoffs. They won the American League Central division by a hair over the Rangers, but they didn't make it to the World Series for the first time in two years. They are looking to continue to build a championship-level team that can have playoff success.
On the surface, it may not appear as though the Astros need outfield help. They have Chaz McCormick in center field and Kyle Tucker in left field. Their defense was in the top 10 in left field according to Outs Above Average, and they had the 5th-best bWAR total for left fielders in all of baseball (1.3 bWAR); however, Jake Meyers and Corey Julks are not household names, and the Astros could use a boost compared to either of those players.
Tyler O'Neill would provide the potential for power in the heart of their lineup, and he would slot in just behind Yainer Diaz. In the 6th or 7th spot in the lineup, O'Neill would lengthen an already potent batting order. His .458 career slugging percentage would place him in the top-5 of the Astros lineup for that statistic.
In exchange, the Cardinals can ask for a variety of players. Houston traded for Justin Verlander last year, only lengthening their rotation. The Astros also have Framber Valdez (free agent after 2025) and Christian Javier (inked a 5-year, $64 million extension that expires after 2027) who could be enticing pitchers for the Cardinals. In their prospect ranks, the Astros could offer Spencer Arrighetti or Colton Gordon. Their farm system is a little depleted, so the Cardinals wouldn't have to give up much in return for either of these players.