15 best trades in St. Louis Cardinals history

#12 - Nolan Arenado (2021)

Cardinals acquire: 3B Nolan Arenado and $50 million
Rockies acquire: LHP Austin Gomber, RHP Tony Locey, 1B Elehuris Montero, 3B Mateo Gil, and RHP Jake Sommers

Total surplus fWAR: 16.7

We've already had multiple Most Valuable Players, Hall of Famers, and World Series champions on this list, and we aren't even to the top 10 yet! Nolan Areando checks in as the 12th best trade in the history of the Cardinals, which is a difficult trade to grade as he's the only active member of the Cardinals on this list at the time of writing it.

Before coming over to St. Louis, Arenado was a superstar for the Colorado Rockies, winning eight consecutive Gold Gloves in all eight big league seasons with the Rockies while mashing 235 home runs and driving in 760 runs on a .293/.349/.541 slash line. It's one of the greatest stretches by a third baseman in baseball history, and is why the Cardinals had targeted him for a number of years.

The Rockies' relationship with Arenado fell apart rather quickly after his eight-year, $260 million extension kicked in, as the club began its descent toward one of the worst teams in all of baseball, and they decided the best thing for both sides was to part ways. Since Arenado would only accept a trade to the Dodgers or the Cardinals, and there was no way the Rockies were going to make their division rival better, a deal with St. Louis came to fruition.

On February 1st, 2021, the Cardinals traded prospects Tony Locey, Elehuris Montero, Mateo Gil, and Jake Sommers along with Austin Gomber in exchanged for Nolan Arenado and $50 million in cash, one of the most complicated trades in club history that took a ton of negotiation between Rockies' ownership and Bill DeWitt Jr. While Gomber provided some production (4.3 fWAR total) as a starter for the Rockies, Montero was a -2.6 fWAR player in Colorado and none of Locey, Gil, or Sommers ever ended up playing in the big leagues.

Arenado, on the other hand, helped propel the Cardinals to the postseason in 2021 before an MVP-caliber season in 2022, where he finished third in voting behind teammate Paul Goldschmidt and Padres third baseman Manny Machado with a .293/.358/.533 slash line to go along with 30 home runs and 103 RBI in a magical 2022 season for the Cardinals. Arenado came up flat in the Wild Card series for the Cardinals, though, as the club was swept by the Philadelphia Phillies in just two games.

During his first three seasons with the Cardinals, Arenado was an All-Star each year, won two Gold Gloves, and one Silver Slugger to go along with that top-3 MVP finish in 2022. Over those first three seasons, Arenado posted a 126 OPS+, slashing .271/.328/.495 with 90 HR and 301 RBI in his first stint away from Coors Field in his entire career.

The last two years have been frustrating for both Arenado and the Cardinals, as they've missed the playoffs the last two years, and since the beginning of 2024, holds just a 98 OPS+ on a .262/.318/.393 slash line with just 26 HR and 110 RBI in 228 games played. While Arenado's defense has bounced back after a weird stretch during 2023 and part of 2024, he's not the same bat he used to be.

Still, Arenado has posted 18.4 fWAR in four and a half seasons with the Cardinals at the time of writing this, including that incredible 7.2 fWAR campaign in 2022. Even though 2021, 2023, 2024, and 2025 have not been prime Arenado years, they have been mostly very productive, and considering the Cardinals gave up virtually nothing to get Arenado and had the Rockies pay them $50 million to help with his contract, this deal will go down as a massive win for St. Louis.

There is still time for this trade to drop down a notch or two on this list or rise a few spots as well depending on how Arenado's time with the Cardinals finishes, but for now, Arenado is firmly within the top 15 trades in Cardinals history and the best deal they've made since 2020 so far.