Reason #3 against promoting him: There's no room for him to play at the majors.
Even with third baseman Nolan Arenado and second baseman Brendan Donovan on the IL, St. Louis Cardinals manager Oli Marmol is trying to squeeze in playing time for Masyn Winn, Nolan Gorman, and Thomas Saggese.
Alec Burleson and Ivan Herrera are rotating between corner outfield duties and designated hitter appearances. There's not much time or space for Wetherholt on the major-league roster as things currently stand.
You don't promote a prospect of Wetherholt's caliber unless you intend on playing him every day. There's an argument that you make the roster work around JJ Wetherholt rather than the other way around, but the focus throughout the 2025 season in the majors has been to give young players full runway to prove their value or lack thereof. Bumping down Thomas Saggese, who is still only 23 and is 11 for his last 41, and Nolan Gorman, who has a .936 OPS over his last 11 games, for Wetherholt is a difficult argument to make.
With Brendan Donovan likely out just a little bit longer and Nolan Arenado starting work in Florida to recover, playing time is about to disappear even more in the final five weeks of the year.
Reason #3 for promoting him: He would bring a spark to a fizzling club.
After floating near playoff contention for most of the year, the Cardinals appear all but out of postseason contention following back-to-back series losses to the Colorado Rockies and New York Yankees last week. They're 18 games behind the Milwaukee Brewers in the National League Central and five back of the New York Mets for the final Wild Card spot.
There isn't much left for fans to be excited about.
A JJ Wetherholt promotion would energize an apathetic fan base ever so slightly. It could also provide a spark to the roster, one that has been replete with injuries of late.
Even if JJ Wetherholt's presence in the starting lineup on a nightly basis adds a few hundred fans, that's attendance that the players and DeWitt family would love to see at Busch Stadium.