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

Many St. Louis Cardinals fans have a propensity to overhype prospects. These 10 players indicate that it's often best to keep expectations measured.
St. Louis Cardinals v Baltimore Orioles
St. Louis Cardinals v Baltimore Orioles / Mitchell Layton/GettyImages
10 of 11

2. Jack Flaherty

Jack Flaherty was taken 34th overall in 2014 and looked the part of a potential ace for the Cardinals after his velocity developed in 2017. Baseball America ranked him as the Cardinals' No. 2 prospect and 53rd in baseball for 2018. He possessed a lights-out fastball and a sharp slider, and for one magical half season, he put it all together in St. Louis. But continual injuries would sap Flaherty of his juice and leave him an inconsistent pitcher for most of his time with the Cardinals.

Flaherty's first full season in 2018 was promising, as he held a 3.34 ERA and finished fifth in National League Rookie of the Year voting. Through the first half of 2019, Flaherty had an underwhelming 4.64 ERA, but he then embarked on a ridiculous stretch through the remainder of the season, holding an 0.91 ERA and winning the Pitcher of the Month award in August and September.

Flaherty looked to have all the momentum in the world, but he stepped back in the shortened 2020 season, with a 4.91 ERA. In 2021, injuries began to bite. After winning his salary arbitration case, Flaherty went on the injured list with an oblique strain. Shortly after returning, he was placed on the IL again, this time with a shoulder strain. He ended the season with a 3.22 ERA.

Flaherty's shoulder continued to bark in 2022, leading him to miss Spring Training and the start of the season. After his third start, he was again placed on the IL with more shoulder woes. He had a 4.25 ERA in only 36 innings on the season.

The Cardinals traded Flaherty to the Baltimore Orioles at the 2023 deadline, and he had massive issues there, with a 6.75 ERA, but he has turned things around since signing with the Detroit Tigers in 2024, holding an ERA of 3.22 with 94 strikeouts in 72.2 innings.

Flaherty's potential was considered sky-high, and what's more frustrating is that fans saw a glimpse of him reaching that in 2019, only for it to be taken away by injuries. That inconsistency, along with his outspoken political statements online, often didn't endear him to the fans, but there's no doubt that when Flaherty was at his best, he was among the most dominant pitchers in the game.