Luke Weaver
Drafter in the first round by the Cardinals in the 2014 MLB draft, Luke Weaver was another piece of the Paul Goldschmidt trade. Weaver was the club's 3rd ranked prospect in 2017, and was thought to be a middle of the rotatoin kind of starter when he fully developed.
Weaver got a couple of chances with St. Louis from 2016-2018 but posted a 4.79 ERA in 233 innings of work. Crazy stat for you, Weaver somehow pitched more innings for the Cardinals than he did for the Diamondbacks, where he spent the significant part of his prime.
Weaver is now a starter with the Cincinnati Reds, and it has not gone well for him this year. He is 0-1 with a 7.71 ERA in 11.2 innings of work. If Weaver can't get things figured out soon, he may be out of the league in the next year or two.