#1 - Dexter Fowler: 5 years, $82.5 million, 2017
Not much of a surprise here. Dexter Fowler was coming off beating the lead-off hitter for the World Champion Chicago Cubs, and the Cardinals decided to pay Fowler to fill the void at the top of their lineup.
Over the four years he played in St. Louis, Fowler slashed .233/.334/.408 with 49 HR and 177 RBI while mostly playing in the corner outfield. For a team that desperately needed outfield help, this was a huge whiff. If they hadn't invested poorly in Fowler, there's a real chance they would have gotten into the Bryce Harper market two years later.
Fowler is a great guy, and while he took a ton of heat during his time in St. Louis, he handled it with class. He had the personality of a Cardinal but did not play up to the standards of his contract. He was traded to the Angels in 2021, and the Cardinals ate $12.75 million of the final year of his contract.