The D-backs agreed to a trade with the Cardinals for veteran third baseman Nolan Arenado, the clubs announced on Tuesday. St. Louis will receive 22-year-old right-hander Jack Martinez -- an eighth-round pick from the 2025 MLB Draft out of Arizona State -- in return.
Arenado is owed $42 million over the next two seasons, and Arizona will receive $31 million in the deal, a source told MLB.com's Mark Feinsand, though the present-day impact for the Cardinals comes out to less than that as St. Louis will pay out the $6 million in deferred money owed to Arenado, which isn't payable until 2040-41.
Arenado had a no-trade clause that he waived for the D-backs.
Arenado, 34, is among the game’s most decorated active players with 10 Gold Gloves, eight All-Star appointments, six Platinum Glove awards, five Silver Sluggers and three NL home run titles.
"I think he's a good fit for us as a team," Arizona GM Mike Hazen said. "We lost some of our position player group last year in the middle of the season when I traded them at the Deadline. So even though I know a lot of the fixation this offseason has been on the pitching, we still felt like adding back to the position player group was important for us. We think he really solidifies our defense on the infield. It's been a priority for us to improve our defense, which I believe is going to have a direct impact on our pitching in a significant way."
Arenado is expected to be Arizona's primary third baseman, a position that had been filled by Blaze Alexander following the team's trade of Eugenio Suárez to the Mariners at last year's Trade Deadline.
With left fielder Lourdes Gurriel Jr. out for at least the first couple months of 2026, Alexander could now see time in either left or center along with prospect Jordan Lawlar, a former first-round pick who is a natural shortstop but got some time in the outfield in winter ball.
Arenado finished third in the voting for the National League’s MVP Award in 2022 – when he slashed .293/.358/.533 (.891 OPS) with 30 home runs and 103 RBIs and won his 10th straight Gold Glove – but his offensive numbers fell off in 2025.
After hitting 26 and 16 home runs in 2023 and ’24, respectively, Arenado’s body started to betray him in 2025 when he suffered back and hand injuries. He was shrouded in trade rumors before the 2025 season, and he used the no-trade clause in his contract to block a potential deal to the Astros. While his defense returned to its normal stellar levels, Arenado hit just 12 homers with a .666 OPS in 107 games.
The Diamondbacks are banking on the fact that Arenado can bounce back from that down year at the plate, during which he slashed .237/.289/.377.
"Last year, I'm sure it didn't go as well as he had wanted it to," Hazen said. "We definitely see the ability to bounce back here. We're excited about that. We know how much work he's going to put into that. As guys get older in this league, and the league evolves, and they need to continue to evolve, and I know he's going to put in every amount of work and energy into doing that. We probably have a little bit better of ballpark to hit in. And so we look for him to be a solid offensive contributor for us in our lineup."
The Diamondbacks aren't looking for Arenado to carry their offense, considering they have a solid core of bats in Ketel Marte, Corbin Carroll, Gabriel Moreno and Geraldo Perdomo.
Arizona also signed free agent right-hander Jonathan Loáisiga to a Minor League deal as it continues to try and build out the bullpen.
More relief additions could be on the way soon, and Hazen said the team would like to also try to acquire a right-handed hitting first baseman/designated hitter to complement the left-handed hitting Pavin Smith.