1. Alex Reyes
The Cardinals' most hyped pitching prospect in many years, Alex Reyes had a sizzling fastball and a devastating curveball, but a black cat must have crossed his path at some point, because there seemed to be no limit of injuries that eventually ruined the blindingly bright outlook for his career.
Reyes signed with the Cardinals out of the Dominican Republic in 2012 for $950,000. After pitching to a 2.49 ERA in 2015, Reyes was suspended for 50 games after testing positive for marijuana. Reyes made his first appearance with the Cardinals in 2016, with a 1.57 ERA in 12 games. Before 2017, he was ranked as the No. 4 prospect in all of baseball.
Before the 2017 season, Reyes was diagnosed with a torn UCL and had Tommy John surgery, missing the season. Returning from injury on May 30, Reyes pitched one inning with the Cardinals before going down with a lat strain, ending his 2018 season.
Reyes spent most of 2019 in the minor leagues after shaky performances in the Cardinals bullpen to start the season. In late April, Reyes broke a finger on his left hand after punching a wall in frustration, leading him to pitch only 28 innings in Memphis.
Reyes was back in the major leagues for the short 2020 season, pitching to an ERA of 3.20. 2021 was Reyes' best professional season. In the first half, he had a 1.12 ERA and saved 20 games as the team's closer, but the second half went poorly, with a 5.52 ERA in 31 innings, and he was removed from the role.
Reyes missed all of 2022 with a shoulder injury, and the Cardinals non-tendered him after the season. He was signed by the Los Angeles Dodgers, but he underwent another shoulder procedure, costing him 2023 as well. The Dodgers did not re-sign him after 2023.
Reyes endured multiple careers' worth of injuries in his nine professional seasons. The pitcher once thought to be a no-doubt ace for the Cardinals might have been able to live up to his potential if health were not a factor, but the constant damage to his body left Reyes as the Cardinals' most bitter disappointment of the past decade.
The Cardinals were able to flip some of the players on this list for some value (Marco Gonzales, Carson Kelly, Luke Weaver), but for others, their luster had been lost and the Cardinals could barely give them away. Whether it was related to injury, performance or both, these 10 players never quite met the expectations that the Cardinals and fans had for them.