As John Smoltz suggested during a segment on MLB Network, a name that makes a lot of sense for the Cardinals to explore is Mark Trumbo. Aside from the statistics, there's an obvious connection between the two teams that would make it easy to explore trade options. This could potentially be a win-win for both teams, as the Cardinals need a first baseman, and for a couple reasons, Trumbo doesn't belong on the Diamondbacks.
Those reasons boil down to Paul Goldschmidt and Yasmany Tomas. For Trumbo to truly survive in an NL environment, he needs to play first base, but with an MVP candidate already entrenched at the position; that's impossible. Because of Goldschmidt, Trumbo has had to play the outfield, and has been unarguably awful. Complicating the matter, and reason number two that Trumbo doesn't belong with Arizona, is that his presence has forced Tomas to play third. Each are almost equally atrocious at their respective positions, but with a six year contract, Tomas should be moved to his permanent spot in the outfield. A trade of Trumbo would also allow for prospect Jake Lamb to play everyday, or as much as the Diamondbacks wanted him to.
With Matt Adams lost for at least three months, and possibly the entire season, the Cardinals will need make some sort of move to upgrade the position. Mark Reynolds is immediate remedy, as he's already on the team and and been slightly better than a league average hitter, but Trumbo is far superior.
PA BB% K% ISO wOBA wRC+
In most categories, Trumbo bests Reynolds. His ISO is at a career high, and his strikeout rate a career low. The Cardinals aren't likely to make a deal in the immediate future, but could target the outfielder at some point soon. Reynolds could be exposed quickly if he plays every day, and may force St. Louis' hand when it comes to a target date.