Nolan Arenado Trade Grades: Cardinals Offload Aging Star in Deal With Diamondbacks

Arenado is headed to the desert.

Arenado is an eight-time All-Star and has won 10 Gold Gloves in his 13-year career. | Joe Camporeale-Imagn Images

After over a year of on-and-off trade rumors, the Cardinals dealt eight-time All-Star third baseman Nolan Arenado on Tuesday to the Arizona Diamondbacks in exchange for righthander Jack Martinez, according to multiple reports. The deal was first reported by Katie Woo of The Athletic. The Cardinals, in the midst of a full-scale rebuild, finally offloaded the 34-year-old Arenado, though the club will be on the hook for $31 million of the remaining $42 million salary on his two-year deal. The Diamondbacks, meanwhile, found a proven veteran to man the hot corner at a palatable price.

Let’s take a closer look at the trade and examine how each club made out.

Cardinals: C+

It’s no secret that the Cardinals have been attempting to deal Arenado, an errand that has been on the to-do list for two different presidents of baseball operations, first John Mozeliak, who stepped down in September, and now Chaim Bloom. In fact, Mozeliak, a little over a year ago, was engaged in discussions with the Astros on a deal that would send cash and Arenado to Houston, but Arenado told the Cardinals he wouldn’t waive his no-trade clause to go to the Astros.

Would the potential return from Houston have been better than what the Cardinals got here? Almost certainly. Especially given the fact that Arenado seems to be a star in decline, particularly at the plate, where he is coming off a season in which he posted an OPS+ of 87, 13% worse than what a league average hitter would have produced. While he remains an above-average fielder, it’s not too surprising that Arenado didn’t net a higher profile prospect than Martinez, who won’t crack the Cardinals’ top 30 prospects in their farm system.

Still, St. Louis didn’t do as badly in this deal as it may seem at first glance. Martinez, Arizona’s eighth-round pick in the 2025 draft, pitched to a 5.47 ERA at Arizona State but showcased the ability to miss bats and control the strike zone at a high level, as evidenced by his 110 strikeouts to 33 walks in 77 ⅓ innings. Even if Martinez isn’t destined to become a big league starter, there’s a foundation to work with here.

On the financial side of things, the Cardinals will be on the hook for $31 million of Arenado’s remaining $42 million in the final two years of his contract. The figure is a bit misleading, though. $6 million of the Cardinals’ portion is in deferred payments from Arenado’s 2019 extension with Colorado, meaning St. Louis is actually on the hook for roughly $25.5 million over the next two years, according to Cot’s Contracts. Plus, that $6 million isn’t due to be paid out until 2040-41, per Mark Feinsand of MLB.com. This might seem like small potatoes in the grand scheme of things. But given how much the Cardinals are on the hook for, any bit of short-term salary relief helps.

Trading Arenado was like ripping off a Band-Aid, but St. Louis’s rebuild has been kicked into high gear after the deals of Arenado, Willson Contreras and Sonny Gray. And with a promising farm system, this teardown might not be as painful as it seems.

Diamondbacks: B

Arenado gives the Diamondbacks something they lacked after trading Eugenio Suárez to the Mariners at the 2025 trade deadline: a proven big-league third baseman. Arenado averaged a .905 OPS from 2015-2022, winning eight straight Gold Gloves while finishing top-five in the National League MVP vote four times during that span. Over the past three years, Arenado has a slash line of .261/.312/.413 for a wRC+ of 99 (156th out of 229 qualified hitters), meaning he’s essentially been a league average hitter. That being said, Arenado has still been worth 6.8 fWAR—90th out of 229 players—given that he’s still adept with a glove.

After trading Suárez, the Diamondbacks handed third base duties to the likes of Blaze Alexander and former top prospect Jordan Lawler—Alexander was a below-average hitter and league-average fielder while Lawler struggled mightily in just 28 games. At worst, Arenado is a short-term upgrade here. Plus, the fact that Arizona was able to acquire the eight-time All-Star for an unproven pitcher in Martinez and will only be on the hook for $11 million of his salary over the next two seasons is a win for the Diamondbacks.

Arizona, just three years removed from a World Series appearance, is definitely betting that Arenado will fight off Father Time, and perhaps benefit from a change of scenery in a more hitter-friendly park in Chase Field. At the very least, Arenado should buy the Diamondbacks enough time to find a long-term solution at the hot corner, whether it’s Lawler or someone else. And if Arenado sinks further into decline, it won’t hurt Arizona too much financially to cut ties with him.

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