Despite having a future NL Champion, a future top 10 prospect and a pitcher who finished 4th in CY Young voting one year, the St. Louis Cardinals top 5 prospects from the 2016 season failed to make a significant impact for the team. Injuries and consistency problems have plagued two of the players on this list, while the other three players were all shipped out in trades down the road. One of those trades was one of the best moves in franchise history. Unfortunately, one of the other prospects played a role in arguably the worst trade in Cardinals history.
This is a series that will feature some prospect overlap due to players not graduating from their prospect eligibility. In those instances, I will post a link to the article they were first introduced in to prevent things from getting repetitive.
1. Alex Reyes - RHP - Current team - Los Angeles Dodgers
2. Jack Flaherty - RHP - Current team - St. Louis Cardinals
3. Luke Weaver - RHP - Current team - Cincinnati Reds
The first of the newcomers to the Cardinals top 5 prospects, the 2014 first round pick quickly rose through the system to become one of the team’s best prospects. He was unbelievable in 2015 pitching to a 1.62 ERA over 19 starts at A+. Then in 2016 he one-upped himself pitching to an even better 1.30 ERA in 13 combined starts between AA and AAA. Those two seasons of dominance lead to his first call up to the bigs in 2016. Weaver did underperform as he had an ERA+ of 72, but he was just 22 years old and only appeared in 9 games. The former first rounder was far better in his 13 MLB games in 2017 as his ERA+ jumped up to 109, meaning he was 9 percent better than the league average pitcher. In 2018, Weaver’s first full season with the Cardinals, he appeared in 30 games, 25 of which were starts. The righties ERA slipped down to 4.95, a number that was inflated largely due to the 19 home runs he gave up. The ‘18 season was his final one with the Cards as they dealt him that offseason to the Arizona Diamondbacks in a package to acquire 2022 NL MVP Paul Goldschmidt. Weaver was strong for Arizona in 2019 as he had an ERA of just 2.94, but he has struggled since. Over the past three seasons he has appeared in 51 games, 26 of which were starts, pitching to a 5.58 ERA. Arizona then flipped him to the Kansas City Royals at the 2022 deadline for Emmanuel Rivera. KC opted to place him on waivers a few months later. The Seattle Mariners claimed him in October, but Weaver became a free agent a few weeks after and signed a 1-year deal worth $2,000,000 with the Reds.
4. Magneuris Sierra - OF - Current team - Atlanta Braves
Magneuris Sierra had an up and down minor league career with the Cardinals. He had two fantastic seasons in which he hit over .300, including his 2014 rookie ball season where he hit .386 over 52 games. However, he also had two seasons in the St. Louis system where he hit .269 or lower. Additionally, Sierra was never a player who offered any type of pop as he hit a combined 10 home runs over his first four minor league seasons. Despite, his lack of power and season by season inconsistencies St. Louis still decided to promote him aggressively. In 2017 the Cards called him up straight from AA even though he had never appeared in a AAA game. In the bigs that season, Sierra had a more than solid .317 batting average across 60 at bats for the red birds. Even with his is strong showing that year the Cardinals shipped him off in the offseason in the ill-fated Marcell Ozuna trade that saw the team also part with Sandy Alcantara and Zac Gallen. Since then, Sierra has largely struggled at the Major League level and been relatively average in the minors. He became a free agent in the 2021 offseason and later signed with the Los Angeles Angels. He was a free agent again this off-season and then agreed to a minor league pact with the Atlanta Braves.
5. Edmundo Sosa - INF - Philadelphia Phillies
Sosa, despite this being the only season in which he was a top 10 prospect in the Cards system, has appeared in 191 MLB games over the past two seasons. In his minor league career for the Cardinals, he posted solid numbers across the board with a lifetime triple slash of .284/.334/.413 through 549 games. In his big-league career those numbers do drop to a still respectable .253/.321/.3778 with 8 home runs. In July of 2022, after a little over a decade with the organization, the Cardinals traded Sosa to the Philadelphia Phillies, for reliever JoJo Romero. Sosa did play in 12 postseason games in 2022 for the eventual NL Champion Phillies.