Toronto Blue Jays
Toronto had an underwhelming 2023 season similar to the Cardinals. While their record was significantly better, they got bounced from the playoffs early and their star players didn't perform up to their usual standards. Toronto appears to have a need for offense from their left field position and third base with the possible departure of Matt Chapman this offseason, and they could use a more consistent designated hitter. Davis Schneider is their current second baseman, and Toronto seems keen on letting him get more run at the major league level.
Toronto has pretty established starting pitchers on their major league roster. Kevin Gausman isn't on the trade block, Jose Berrios seems to have found his way back, Chris Bassitt just signed a contract with them, and Alek Manoah may be too damaged for the Cardinals to want to trade Brendan Donovan. Dylan Carlson appears to be a more likely trade piece for Alek Manoah.
The Blue Jays do, however, have one top prospect that may be enticing to the Cardinals: Ricky Tiedemann. The left-handed pitcher out of Golden West College was drafted in the third round of the 2021 draft. Tiedemann has added velocity to his fastball and has a very strong changeup. His sweeper needs some work to become a true third pitch. Tiedemann could work to improve his control, but he has a ceiling of a top-end starting pitcher down the road.
Toronto was aggressive with the 20-year-old pitcher, pushing him across all minor league levels last year and sending him to the Arizona Fall League. In 44 regular season innings, Tiedemann had a 16.77 K/9 ratio, a 4.70 BB/9 ratio, and a 3.68 ERA. In just 18 Fall League innings, he has a 2.50 ERA, 1.111 WHIP, and 11.5 K/9 paired with 4.0 BB/9.
Ricky Tiedemann is ranked as the #31 overall prospect in all of baseball. For context, Matthew Liberatore was the 55th-ranked prospect in 2020, the same winter he was dealt to the Cardinals for Randy Arozarena, a player who wasn't ranked in the top 100 that same season. It is very possible that Brendan Donovan and Tiedemann could be swapped for each other straight up.