Cardinals receive: RHP Logan Gilbert
Mariners receive: 2B Nolan Gorman and RHP Giovanny Gallegos
Let's get this out of the way to start. Starting pitchers are typically valued higher in the trade market than position players, especially young starters with team control. Logan Gilbert is not coming to come cheap for the Cardinals.
Honestly, I'm not really sure the Mariners will want to part with him without getting a haul in return. They do not need to deal him, and so I can see them playing hardball here.
Nolan Gorman I think has to start the conversation, especially with Lars Nootbaar being off-limits in the Cardinals' mind. Gorman would provide high upside thump to the Mariners lineup, and Giovanny Gallegos is a strong second piece that bolsters the Seattle bullpen even more for a run this year and in future years.
Gilbert has a 3.66 ERA this season but is coming off a 2022 season where he had a 13-6 record with a 3.20 ERA in 185.2 innings. Gilbert would be under team control through the 2027 season, giving the Cardinals a much needed arm for years to come.