Star Third Baseman Named Good Fit for Diamondbacks

Mike Petriello, Stats Analyst for MLB.com wrote an article on top trade fits for the St. Louis Cardinals third baseman Nolan Arenado.

The Cardinals have made it clear that they are rebuilding and shedding payroll. They just traded Sonny Gray to the Red Sox, and sent $20 million along with him.

Arenado is sheduled to earn $27 million in 2026 and $15 million in 2027. $5 million of the 2026 salary is being paid by the Colorado Rockies, meaning the actual amount to be discussed between the Cardinals and any trade partner is $37 million.

The question becomes, what is Arenado's actual value at this point, and how much should any team, including the Diamondbacks, be prepared to absorb of that $37 million? We'll get to that further down in the article.

The question as it pertains to the Diamondbacks: is it worth it to pursue Arenado, considering they received good production overall from Blaze Alexander over the final two months of the season?

Petriello points out that Blaze Alexander was just "fine" at the plate, posting a 95 OPS+ (slightly below league average). Furthermore his versatility, being able to play second base, shortstop, and outfield might make him more valuable as a super utility player than as an every day third baseman.

The other possibility of course is that the Diamondbacks trade Ketel Marte to shore up their pitching, thus opening up second base for Alexander full time, and making a spot for Arenado. While nothing seems imminent on the Marte trade front, the rumors are persistent.

Related Content: These 2 Teams are Calling About a Ketel Marte Trade

Noland Arenado's Decline

Nolan Arenado has already played his way into a borderline Hall of Fame Career.

He has been the best defensive third baseman of the last 20 years, and during his peak years in Colorado and first couple of years in St. Louis was an offensive force. Here he is compared to other third basemen since 2008 using advanced metrics:

Arenado has been a shadow of his former self at the plate the past three seasons, however, and while his defense is still somewhat above average, he is no longer the premier defender at the position.

Over the last three seasons he has averaged .261/.312/.413, .725 OPS or 101 OPS+, with 18 homers and 72 RBI. But it was in 2025 where things really went south. He batted just .237/.289/.377, .666 OPS, or 87 OPS+.

Arenado was fine for his first 37 games, batting .270 with a .778 OPS. But over his final 73 games the bottom fell out. He hit .228 with a .630 OPS. He also spent six weeks on the injured list with a sore right throwing shoulder between July 31 and September 15.

As one might suspect, the bottom also dropped out of his underlying quality of contact and bat metrics. His Barrel rates have been cut in half the last two years to 3.2% and 3.9%, which is roughly half the major league average.

His average bat speed has been stable, but barely league average, while his swing registers longer than the league average.

On defense Arenado still managed to record +6 defensive runs saved in each of the previous two seasons according to Baseball Reference. Over at Statcast, his fielding run value was +7 in 2024 and +2 in 2025. As stated, he's still above average with the glove.

What is Nolan Arenado's Current Value?

Due to his glove still being above average, and at least some potential for a bounce-back at the plate if his shoulder is fully healed, Arenado should be worth at least one WAR, and potentially as much as two.

Typically one WAR is considered to be worth $8 million on the free agent market, although that is not a hard-and-fast rule of course.

The Diamondbacks could consider taking a chance on Arenado for approximately two years, $16 to $18 million, meaning the Cardinals would have to absorb between $19-21 million of the contract (with the Rockies still paying their five).

Of course the D-backs would still need to kick in a prospect, but it should not be anyone within their top 15. This deal has to be strictly about salary relief for the Cardinals. If they expect a top 15 or better prospect in return, the D-backs should pass.

If they made such a deal, and went ahead and moved Marte for pitching, and slid Alexander over to second base, the pieces could fit. Overall the D-backs' offense would clearly take a hit. But the defense would be better, as would the pitching presumably, based on the return for Marte.

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