Reason #2 against promoting him: He's only played 26 games at Triple-A.
This is a very small sample size of games. The gap between Triple-A and the majors has also never been greater than it is now. It's wonderful that he's tearing the cover off the ball in the minors, but he needs to prove that he can sustain this level of production for an extended period of time.
After seeing the results of promoting players too early with Dylan Carlson and Jordan Walker, one would think that the Cardinals would approach this situation with caution.
Memphis has 30 games left on their schedule. If he plays the remainder of the season with the Redbirds, he'll have a sample size greater than 50 games and 200 plate appearances. That's a meaningful collection of data that the organization can evaluate this winter and into spring training next year to see if he's ready for the big leagues.
Furthermore, Wetherholt has only played five games at third base this year as a prospect. If third base is the organization's preferred position for him in the future, he should learn the position more before being promoted.
Reason #2 for promoting him: There are ample benefits to seeing the majors, even for a little bit.
Major League Baseball is a beast.
I'm not just talking about the level of competition, which far exceeds any other level of baseball in the world. Traveling is different, the clubhouses and stadiums vary dramatically from the minors, even travel is drastically different.
Promoting JJ Wetherholt now will help him get his jitters out of the way for 2026 when he could be a full-fledged starter. It also allows him to familiarize himself with baseball in the big leagues.
When the Cardinals promoted shortstop Masyn Winn on August 18, 2023 for the final stretch, he took that experience as a time for learning. He slashed just .172/.320/.238 in 2023, but he used that experience to launch him into a 4.9-bWAR rookie season in 2024. He's not on pace to finish with more than three bWAR this year and a shot at a Platinum Glove.
Winn played 105 games in Triple-A that year, four times as many as Wetherholt has up to this point. However, Wetherholt came to St. Louis a polished collegiate athlete. Winn was drafted out of high school three years prior to his promotion. The level of competition that Wetherholt has faced throughout his career should be ample preparation for the big leagues.