6. Matthew Liberatore
The Cardinals traded for Matthew Liberatore in January of 2020 in possibly one of the worst trades in recent memory for John Mozeliak. Liberatore, a former first-round pick in 2018, was a left-handed pitcher with a wicked curveball and strong strikeout numbers. He advanced through the minor leagues quickly and made brief appearances with the Cardinals in 2022.
The 23-year-old southpaw has pitched 96 innings at the major league level to the tune of a 5.51 ERA, 4.54 FIP, 1.567 WHIP, and he has struck out a total of 74 batters. His career 17% strikeout rate and 9.9% walk rate are both significantly worse than league average, and his once-dominant curveball has a negative run value according to Baseball Savant (-5 in 2023 and -1 in 2022).
Perhaps the most redeeming aspect of LIberatore's trade value would be his age and team control. He'll be 24 for the entire 2024 season, and he has 6 years of control left with three years at the league minimum dollar figure. Libby is a former top prospect, and he is still young. A team may be interested in trading for him now so they can continue to correct what's been going wrong with him.
Liberatore isn't the least valuable Cardinal, but his major league performance thus far has definitely lowered his value overall.