By Andy McCullough, Cody Stavenhagen and Sam Blum
Diamondbacks get: 3B Nolan Arenado, cash
Cardinals get : RHP Jack Martinez
Andy McCullough
Diamondbacks: B
Cardinals: B-
It is hard to envision a scenario in which the Baseball Hall of Fame ever features a bust of Nolan Arenado wearing an Arizona Diamondbacks cap. But if Arenado wants to be enshrined in Cooperstown, his upcoming tenure with Arizona could play a pivotal role. With St. Louis hankering to shed Arenado’s contract, the Diamondbacks are taking a relatively low-cost flier on a player who was once one of the best in the game. What does he have left?
Arenado has a borderline resume for the Hall of Fame: 10 Gold Gloves (and six Platinum Gloves), eight All-Star appearances, five Silver Slugger awards, four top-five MVP finishes. But he has faded considerably across the past three seasons. He posted a career-low 87 OPS+ and appeared in only 107 games. As Arenado enters his age-35 season, the Diamondbacks have to hope that he can retain his elite strike-zone management while improving his shockingly low exit velocity numbers. His days of hitting 30 homers may be over, but Arenado may benefit from leaving Busch Stadium for the more hitter-friendly confines of Chase Field.
The Cardinals were willing to pay $31 million of the $42 million left on Arenado’s deal, which should give you some sense of their faith in his short-term prospects. That’s a lot of money to eat, given the lack of prospects coming back to St. Louis, but Arenado’s no-trade clause complicated matters. The Cardinals felt compelled to move him, and now they have.
Cody Stavenhagen
Diamondbacks: B
Cardinals: C-
Nolan Arenado is a big name. The Diamondbacks are a team signaling an intention to be contenders in 2026. For those reasons, this trade will get a lot of attention.
In reality?
Arizona is acquiring a third baseman well past his prime. The Cardinals are getting an eighth-round pick and little financial relief in return.
Circumstances were difficult for the Cardinals this time a year ago, but St. Louis absolutely could have gotten more — and paid less — in an Arenado deal had they moved him last offseason. In 2025, Arenado posted a 0.9 fWAR season and displayed further evidence that his batted-ball metrics are never returning to his prime levels. Now Arenado is entering his age-35 season. His wRC+ has ticked down in three consecutive years, from 149 to 107 to 103 to 84.
The Diamondbacks are giving up little and getting a great sale price on Arenado’s contract. If his defense alone remains above average, it could improve their team. Helps, too, they are expected to keep Ketel Marte. This is a good fit, but let’s not act like Arenado is still in the same class as Alex Bregman.
Sam Blum
Diamondbacks: B-
Cardinals: B+
On the surface, this appears to be a cheap and low-risk acquisition for the Diamondbacks. But even for a player of Arenado’s immense talent and name recognition, this might be an overpay.
Arenado has been in steep decline offensively. His average exit velocity is in the bottom 10 percentile of all MLB hitters — leading to a notable drop in nearly all of his expected offensive metrics.
Last season, Arenado had an OPS+ of just 87, meaning he was below replacement level. His .377 slugging percentage was way down from his .501 career average. Normally one of the most durable players in the sport, Arenado missed nearly two months with a shoulder injury toward the end of last season.
The Diamondbacks didn’t give up much to get Arenado. It’s essentially just an $11 million cash considerations deal. Yes, Arizona sent over a prospect. But he’s an eighth-rounder yet to throw a professional inning.
For a player of Arenado’s pedigree, $11 million sounds like a bargain. But if his offense continues to decline, and his once-elite defense isn’t there to save him, that aforementioned pedigree won’t be worth the paycheck.
Arenado may be a Hall of Famer. And there might be more left in the tank — particularly moving to a competitive team that wants him, and that plays a hitter-friendly park. But the risk exists that, at age 35, he just isn’t a viable contributor. His statistical trajectory suggests that’s very possible.
So yes, on paper, this looks like a bad deal for the Cardinals. But we also don’t know how hamstrung they were by Arenado’s no-trade clause. Ultimately, they recoup some cash, get a lotto ticket prospect, and move forward with an opening for prospect JJ Wetherholt at third base.
It’s a tough $31 million to swallow, but those are the inherent risks of acquiring players with massive contracts. Their value was front loaded, and Arenado was an All-Star his first three seasons in St. Louis. They made the right deal for them regardless of what happens. Arizona hopes it can say the same.
