Dexter Fowler
Expectations were high for Dexter Fowler when he signed a five-year, $82.5 million contract with the Cardinals in 2017. Fowler had a respectable first season in St. Louis, where he hit .264, but his average cratered in 2018 to .180. Not only was he poor offensively, Fowler also heavily regressed in the outfield, leading some fans to believe that he no longer cared and was just playing for the contract. Fans weren't happy with the high-priced acquisition's poor play, and the issues were exacerbated when John Mozeliak criticized Fowler for a lack of effort.
This wasn't the first controversy that Fowler found himself mired in during his Cardinals tenure. In 2017, Fowler spoke of then-President Donald Trump's ban on travel to his wife's home country of Iran, saying "It's hard. Especially anytime you're not able to see family, it's unfortunate." Many fans online did not take kindly to Fowler's comment, with some saying he should not bring up politics and would not be a good fit in St. Louis.
Fowler's inability to live up to his hefty contract undoubtedly played a large role in his lukewarm reception from Cardinals fans and from Mozeliak, and his icy relationship with Mike Matheny, the manager at the time, didn't help matters. The Cardinals eventually ate the last year of Fowler's contract after trading him to the Los Angeles Angels in 2021.