The Cardinals' second pick in the 2014 draft and one of their top prospects for a few years, Jack Flaherty had an astonishing second half of 2019, where he pitched to a 0.91 ERA in 15 starts. Unfortunately, injuries in 2020 and beyond kept him from reaching those heights again.
Cardinals fans were often irritated that Flaherty couldn't stay healthy enough to flash that 2019 production, and off the field, Flaherty's willingness to speak out publicly about the Black Lives Matter movement and his support of kneeling during national anthems led to a backlash among fans. He also had some brushes with the media, once noting that a reporter "doesn't understand pitching" when Flaherty was asked about his reduced velocity.
Flaherty, born and raised in Los Angeles, was frequently accused by fans of wanting to play for his hometown Dodgers. Many believed he would bolt for Los Angeles as soon as he could, which wasn't helped by Flaherty's arbitration case, an often nasty dispute between players and teams, after Flaherty and the Cardinals couldn't agree on a salary.
The Cardinals traded Flaherty to the Baltimore Orioles at the 2023 deadline, after which Flaherty aired some thinly veiled criticism at Cardinals fans, saying he "hasn't had to turn his PitchCom up while pitching at home in a while" after his first start in Baltimore.