Triston Casas
Though Chaim Bloom wasn't in Boston when Triston Casas was drafted in 2018, Bloom was Boston's chief baseball operator for virtually all of Casas's development. Therefore, Chaim is quite familiar with the Red Sox's young first baseman.
There aren't any true rumors that the Red Sox are shopping Casas at this moment, but Casas himself found it necessary to discuss the trade rumors earlier this month. He expressed a desire to remain in Boston, but he also said that he understood the business side of things. The young first baseman would net quite a return given his age and talent, so it makes sense the Red Sox are possibly shopping him to improve their pitching.
Casas is a career .250/.357/.473 hitter for an OPS+ of 125. He's hit 42 home runs in 222 games. He's been down with a couple of injuries for his career, most notably a right shoulder injury that hampered him last year.
Casas isn't arbitration-eligible until 2026, and he won't be a free agent until 2029. The team control here is virtually unheard of. His skill, years of control, production, and price would make him a costly commodity. The Cardinals would have to part with one major league player (Ryan Helsley, perhaps?), and likely two of their top prospects. Think Tink Hence or Quinn Mathews plus Chase Davis possibly.