Pete Alonso's Orioles Deal May Provide Opportunity for D-backs

The former Met's massive deal could allow the Arizona Diamondbacks to make a first base addition.

Sep 28, 2025; Miami, Florida, USA; New York Mets first baseman Pete Alonso (20) reacts while standing next to shortstop Francisco Lindor (12) after his at bat against the Miami Marlins during the fifth inning at loanDepot Park. Mandatory Credit: Sam Navarro-Imagn Images | Sam Navarro-Imagn Images

All-Star first baseman Pete Alonso signed a five-year, $155 million contract with the Baltimore Orioles on Wednesday, and that massive deal might backhandedly help the Arizona Diamondbacks in their pursuit of a first baseman.

Numerous outlets had previously pushed Alonso as an unrealistic target for the D-backs. That was never going to be an option. But Alonso's decision could potentially help Arizona land their first baseman this offseason.

The D-backs have had a hole at first base ever since trading Josh Naylor away to the Seattle Mariners at the 2025 Deadline. Their platoon rotation of Pavin Smith, Tyler Locklear Tim Tawa and Ildemaro Vargas were unproductive as a collective following the deal.

That leaves first base as an area of need for Arizona. And with the Alonso deal, first base becomes an area of wealth for Baltimore.

Why Pete Alonso Deal Could Help D-backs

Sep 21, 2025; Baltimore, Maryland, USA; Baltimore Orioles designated hitter Ryan Mountcastle (6) stands in the dugout before the game against the New York Yankees at Oriole Park at Camden Yards. Mandatory Credit: Tommy Gilligan-Imagn Images | Tommy Gilligan-Imagn Images

With the addition of Alonso, the Orioles now have three right-handed hitting options at first base. Alonso will certainly be the everyday option, with Ryan Mountcastle and Coby Mayo both in the fold as well.

If the D-backs are looking to make an addition at first base via trade, it would be difficult to imagine the Orioles not at least fielding some calls on Mountcastle or Mayo.

Mountcastle is coming off a down season in which he spent half the year on the IL with a hamdstring strain. With that in mind, his .653 OPS makes a little more contextual sense.

But he's been an above-average hitter every other year of his major league career, and at least an around-average defender. Mayo, meanwhile, has not had much success at the plate (.634 career OPS), but is only 23 years old with 340 total plate appearances.

Of the two, Mountcastle would be the more desirable player, although he is in his last year of arbitration. The Diamondbacks could use him as a stopgap until Locklear has some more time to develop, and just one year of control could make him a slightly more affordable acquisition.

But there remains an uncertainty surrounding Arizona's first base situation.

If Locklear is able to emerge as a legitimate future option, that would benefit the D-backs greatly. But after he struggled in 2025, and eventually underwent surgery to both his elbow and shoulder, Arizona will be forced to explore their other options.

The D-backs have also been linked to former franchise legend Paul Goldschmidt, who might be willing to return to Arizona on a semi-affordable one-year deal in a platoon role.

So far, there hasn't been much movement from the D-backs this offseason, with the exception of a reported lower-scale one-year deal with former Nationals and Cubs pitcher Michael Soroka.