Kolten Wong
With the addition of Matt Carpenter, adding Kolten Wong seems a bit unnecessary right now. And, the Cardinals definitely shouldn't bring back Wong with the roster as currently constructed. However, if injuries pile up and the Cardinals find themselves lacking infield depth as they did at times last season, bringing back another fan favorite in Kolten Wong to fill late innings as a defensive replacement at second base and pinch hit against right-handed pitchers would be a welcome move.
Wong's two seasons with the Brewers were quite good offensively, recording a combined 113 OPS+ between the two seasons. Unfortunately, after being dealt to the Mariners prior to the 2023 season, his offensive output completely vanished. In 216 plate appearances, he recorded a slash line of .165/.241/.227/.468 for a 34 OPS+. He found some success after joining the Dodgers in a bench role, but it seems Wong's best days are ahead of him.
Still, if the Cardinals are ever in need of a depth infielder midseason, Wong could slot in perfectly if he doesn't sign with another club. He's only 33, so he could still bounce back after a rough 2023 season, and at the very least provide a jolt off the bench or as a plus-defender in late innings. With the Cardinals' defense struggling so much in 2023, Wong could be a fitting reunion should they need it.
Matt Holliday
Here's one that almost came to fruition last season. Matt Holliday was initially hired as the Cardinals bench coach, but he backed out after realizing he wasn't ready to take on a coaching role, prioritizing family instead. If Holliday is ready for a role with the Cardinals organization now, he'd surely be welcome back with open arms.
With the Cardinals clearly searching for leadership in the clubhouse, adding Holliday to the coaching staff would be another great step. Daniel Descalso has filled the bench coach role that Holliday was slated to take last offseason, but the front office could find other roles for him to fill, perhaps those that don't require full commitment during the season.