"But the Cardinals already have an aging first baseman!" Yes, they do. Why not have another who can bat left-handed and has been one of the best first basemen since 2007? Joey Votto's veteran presence, positive attitude, and experience would benefit the team. He can only play first base or DH anymore, so his defensive versatility is lessened.
Votto has excelled against right-handed pitchers in his career. He would provide balance to a lineup that has historically mashed lefties and struggled against righties. His plate approach has always been strong given his career 16.1% walk rate and 19% K rate. Votto doesn't chase bad pitches (18% chase rate), and he is still one of the best players at barreling baseballs (78th percentile in 2023).
Should the Cardinals sign Joey Votto, they'll also be able to tout the fact that they poached a player from a division rival in the Cincinnati Reds. From a logistic perspective, it doesn't make sense to sign Joey Votto. St. Louis has Alec Burleson and Matt Carpenter on the bench as left-handed batters who provide more positional flexibility than Votto would, but signing Joey Votto would still be fun.
Whit Merrifield would be a more useful bench player than Joey Votto. The most useful aspect of a Merrifield signing would be his versatility on the defensive side of the ball. He has played in both corner outfield spots, second base, first base, and third base in his career. With Dylan Carlson, Matt Carpenter, Alec Burleson, and Ivan Herrera as the team's presumptive bench players, the Cardinals could use someone who can play these positions aptly.
Merrifield is also one of the fastest players in the league still. His sprint speed in 2023 placed him in the 85th percentile in baseball, and he stole twenty-six bases. That figure would have placed him second on the team last year behind only Tommy Edman. Whit can be a late-inning bench bat or pinch runner who can provide solid defense at multiple positions. Merrifield's presence in the clubhouse would also be a boost.
Before the end of last season, I discussed the benefits of signing Cody Bellinger. He can play both center field and first base at a well above-average clip, and his bat, for as unpredictable as it may be, has the potential to be one of the best in baseball.
It's a bit of a gamble with which version of Cody Bellinger a team will get next year. It's possible he will return to his MVP form of 2019 and has a ridiculous power surge. Maybe he changed his swing again this offseason, leading to a season similar to his terrible 2021 season. Perhaps Bellinger maintains his bat-to-ball skills from last year while sacrificing walks.
Regardless of the offensive form of Cody Bellinger, a team can be assured that Bellinger's speed and defense will be superb. The Cardinals could place Bellinger in center field if Masyn Winn isn't ready, he can play first base if Goldschmidt needs a rest (and in 2025 and beyond if the Cardinals don't extend Goldschmidt). The roster would get clogged again, and Belly would cost a pretty penny, but his addition to the team in 2024 would be an immediate upgrade.