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After more than a yearlong residency on the rumor mill, Nolan Arenado’s time in St. Louis is over. The Cardinals announced Tuesday that they’ve traded Arenado and cash to the D-backs in exchange for minor league right-hander Jack Martinez (Arizona’s eighth-round pick in the 2025 draft). The Diamondbacks are reportedly on the hook for a total of $11MM of the remaining $42MM owed to Arenado over the next two seasons. The Cardinals owe the remaining $31MM. Arizona’s 40-man roster had a vacancy but is now at capacity with the addition of Arenado.

With the Cardinals entering a rebuild under new president of baseball operations Chaim Bloom, trading the 34-year-old Arenado (35 in April) has been a primary goal this offseason. St. Louis has finally achieved that goal but paid a hefty price to do so. Arizona will be on the hook for just $5MM this season and $6MM next year.

Three years ago, a salary dump of Arenado would’ve been hard to imagine. He was a National League MVP finalist after hitting .293/.358/.533 with 30 home runs and his typical brand of elite defense during that 2022 season. His offense slipped considerably in 2023 (.266/.315/.459) but was still north of league average. It dipped to about average in 2024, however, and plummeted well below par this past season.

In 436 plate appearances with the Cardinals in 2025, Arenado turned in an anemic .237/.289/.377 batting line. By measure of wRC+, he was 16% worse than an average hitter at the plate. Arenado’s 12 home runs were his lowest in a full season since his rookie year back in 2013. This year’s 6.4% walk rate was his lowest since 2015. When considering that his 34.1% chase rate on pitches off the plate was also his worst since 2015, that’s not particularly surprising. Arenado’s 11.2% strikeout rate was one of the lowest in MLB and one of the best in his career, but he also posted his highest-ever infield fly rate — 16.5% of his fly-balls were harmless pop-ups — and recorded some of the worst exit velocity and hard-hit numbers of his career.

Suffice it to say, Arenado’s decline at the plate has been steep. He still possesses plus contact skills but will need to scale back his chase rate and cut out some of those weak pop-ups if he’s to improve in a meaningful way. Fortunately for Arenado, he’s going to a more favorable offensive environment than the one he’s been calling home in St. Louis. While Phoenix’s Chase Field isn’t the hitters’ haven it once was, it plays largely neutral to right-handed power now — a stark gain for Arenado relative to St. Louis’ Busch Stadium, which is the fifth-worst park for right-handed home run power over the past three years, per Statcast’s Park Factors.

Prior to adding Arenado, the Diamondbacks had been involved in the market for Alex Bregman. A match there always seemed like something of a long shot, given Arizona’s intent to reduce payroll in 2026, but the interest was legitimate. The Snakes quickly pivoted and brought in a much more affordable option to hold down the hot corner for the next two seasons. Arenado’s glove has also taken some steps back in recent years, but he’s still an above-average defender. He’ll give manager Torey Lovullo a quality pair of defenders on the left side of the infield, joining breakout shortstop Geraldo Perdomo in that regard.

Acquiring Arenado leaves the Diamondbacks with little opportunity for former No. 6 overall pick and top prospect Jordan Lawlar. Perdomo’s breakout appeared to push Lawlar down the defensive spectrum to third base, but he looked overmatched both with the glove and in the batter’s box during his first few tests against MLB pitching. The D-backs were considering giving him some time in the outfield, and perhaps with Jake McCarthy now in Colorado following this weekend’s trade, there’ll be a clearer path to that experiment. If not, Lawlar has a minor league option remaining and can be sent back to Triple-A (where he’s routinely thrashed opposing pitchers) — or even included in a potential trade package to address needs elsewhere on the roster.

Even with the Snakes looking to cut payroll, the addition of that fraction of Arenado’s contract amounts to little more than a footnote. He’s effectively replacing a league-minimum player, so this trade adds a net $4.2MM to the team’s books. Per RosterResource’s estimates, that brings Arizona’s payroll just north of $170MM. That’s more than $17MM shy of last year’s Opening Day payroll. An exact target isn’t clear, but there should be room to add a reliever or two, at the very least, and further trades could always change the payroll outlook one way or another.

If the money changing hands (and the frequent reporting in the year-plus leading up to today’s trade) wasn’t indicative enough that this amounts to a salary dump for St. Louis, the return should be. Martinez hasn’t pitched an inning in professional ball yet. The Diamondbacks selected him with their eighth-round pick last year out of Arizona State University. His $167K signing bonus checked in south of his No. 243 overall selection’s $223K slot value.

A 6’4″, 215-pound righty, Martinez started his college career playing Division-III ball before transferring twice and ending up in the Sun Devils’ rotation as a senior. He was tagged for a 5.47 ERA through 15 starts during his senior year. It’s not an encouraging number, but Martinez punched out 32.3% of his opponents and can run his fastball up to 97 mph, per MLB.com’s scouting report. He has a four-pitch mix with a changeup serving as his best secondary offering, but Martinez is a pure lottery ticket for the Cardinals’ reshaped player development department.

A year ago, the Cardinals thought they had worked out a trade to send Arenado the Astros. Arenado, however, invoked his no-trade protection to nix that arrangement, reportedly due to reservations about the Astros’ commitment to contending; Houston had just traded Kyle Tucker to the Cubs days prior to the nixed Arenado deal. Heading into the current offseason, Arenado was forthcoming about the fact that he’d be more open-minded to offseason trade scenarios than he was last winter.

That clearly seems to be the case, but the D-backs might’ve been a viable landing spot for him even if he were continuing to remain selective. Arizona may be scaling back payroll, but their signings of Merrill Kelly and Michael Soroka — plus their reported interest in the aforementioned Bregman — all signal a commitment to try to field a contender in 2026. Beyond that, Arenado is a Southern California native with a home in Arizona. There are geographic benefits that surely played into his decision to waive that no-trade clause for a move to the desert.

For the Cardinals, moving Arenado now clears a relatively nominal sum from the long-term books and furthers their goal of creating opportunities for younger players. It remains to be seen whether Arenado’s third base reps will go to Nolan Gorman, top prospect JJ Wetherholt or even former top prospect/third baseman-turned-outfielder Jordan Walker. Whoever takes up regular work at the hot corner will be a more viable long-term option at the position than Arenado is as he enters his mid-30s.

The trade of Arenado is the third of a big-name veteran on a large contract for the Cardinals this offseason. They’ve already traded Sonny Gray and Willson Contreras to the Red Sox. Those players were shipped out in separate deals, with St. Louis eating notable portions of money in those trades, too. Between Gray, Contreras and now Arenado, the Cardinals will be shelling out $59MM over the next two seasons to three players who are no longer on their books.

Eating that amount of money to facilitate the trades of three former All-Stars is unprecedented, but the Cardinals have been clear about their intent to rebuild the organization from the ground up, modernizing the player development department, analytics staff and various other components of the team’s baseball operations setup — all while affording younger and more controllable players the opportunity to establish themselves in the majors. With three pricey veterans gone, much of the heavy lifting has been taken care of, but the Cardinals are still widely expected to trade second baseman Brendan Donovan and left-handed reliever JoJo Romero before the season begins.

Katie Woo of The Athletic first reported that the two sides were in serious discussions. John Gambadoro of 98.7 FM Arizona Sports broke the news that an agreement was in place and added that Martinez was going back to St. Louis. Nick Piecoro of the Arizona Republic first reported details on the cash changing hands.