Looking back at the Cardinals' 10 most disappointing prospects of the past decade

4. Carson Kelly

Drafted in the second round at No. 86 in 2012, Carson Kelly was selected as a third baseman but converted to catcher in 2013, as the staff hoped he would be the eventual successor to Yadier Molina as the Cardinals' starting catcher. But as Molina kept chugging along behind the plate through his later years, Kelly continued to spend most of his time in the minor leagues, leading him to appear on Baseball America's top Cardinals prospects lists six years in a row and peak at 55th out of all prospects.

Kelly was originally a glove-first backstop, but in 2016, he found a new gear with his bat, hitting .289 in 362 plate appearances with the Cardinals' Double-A and Triple-A affiliates. That season, he received 75 plate appearances with St. Louis but hit only .174.

The Cardinals realized that Kelly wasn't going to get any younger, nor was he receiving meaningful major league experience behind Molina, so after Kelly hit a combined .154 across parts of three seasons with the Cardinals, they traded him to the Arizona Diamondbacks as part of the Paul Goldschmidt deal on Dec. 5, 2018.

The deal worked out well for the Cardinals, as Goldschmidt won the MVP in 2022. With Arizona, Kelly hit .230 over four-plus seasons as the starting catcher before being released in August of 2023 and signing as a free agent with the Detroit Tigers.

Kelly has developed into a starting catcher in the major leagues, but he was never going to get his shot to evolve as a player in St. Louis. Molina's presence was a welcome one for so many years, but it can't be denied that it stunted the growth of catchers like Kelly.