5 big takeaways from the Arenado trade

Nolan Arenado was introduced to Cardinals fans via Zoom in February 2021 as someone who could not wait to play for the Cardinals as long as possible, and to win every year.

The Cardinals had put together 13 consecutive winning seasons heading into that year, while Arenado’s previous team, Colorado, was two years into a streak of seven consecutive losing seasons. The Cardinals were always good, and now they had Arenado. “[Losing is] something I'm not worried about with St. Louis,” he said.

Arenado certainly had his moments with St. Louis, but his time at Busch Stadium didn’t quite turn out the way he and everybody else thought it would. St. Louis made the playoffs in his first two seasons with the team -- but played in only three total postseason games, losing all of them. The club proceeded to post a losing record in two of Arenado’s final three seasons, matching the franchise’s total of sub-.500 campaigns from 1998-2022 combined.

On Tuesday, Arenado’s time in St. Louis ended with a long-awaited trade, as the Cardinals sent him to the Diamondbacks for cash and right-hander Jack Martinez, an eighth-round pick in the 2025 MLB Draft who is not on the Cardinals’ Top 30 prospects list, per MLB Pipeline.

Here are five immediate takeaways from the deal:

1. The Arenado saga is finally over in St. Louis
One of the biggest worries for the Cardinals and their fans as the calendar turned to 2026 was that Arenado would still be on the roster when Spring Training begins in February. After all, an awkward Arenado arrival in Jupiter, Fla., after an offseason of failed attempts to trade him just happened last year.

That’s not to say that it’s a contentious split or anything, but Arenado has not been a fit on this St. Louis roster for a while now. And that’s especially true in 2026, with new president of baseball operations Chaim Bloom trying to orchestrate a rebuild and clear space for young talent.

The Cardinals were so certain they would trade Arenado that manager Oliver Marmol let him come on the field on the last day of the 2025 season and then immediately replaced him, assuring he’d get one final ovation from the Busch Stadium faithful. With Arenado’s no-trade clause and his declining value, that was not a certainty. But now it has happened, and St. Louis can move on.

2. The D-backs got better, but they really need an Arenado revival
Eugenio Suárez was a monster for the Diamondbacks last season before they sent him to the Mariners at the Trade Deadline. Replacement Blaze Alexander was, well, less than a monster. Trading for Arenado makes him Suárez’s real replacement for the next couple of seasons, which is why it should probably be said that Arenado’s offensive numbers in 2025 were weaker than Alexander’s.

Arenado had the worst offensive season of his career, by a large margin, in 2025, and he particularly struggled in the second half, hitting .175 in July (with no homers) and .250 in the regular season’s final month. He’s still a defensive dynamo and a veteran clubhouse presence, but if he’s just giving you last season's numbers, it’ll be a disappointment. Nobody is expecting Arenado to return to the 2022 form that had him finish third in NL MVP Award voting, but even getting back to around league average at the plate -- where he was in 2023-24 -- would be a win for Arizona.

3. Now, the Cards can turn their full attention to Brendan Donovan
The two theoretical deals were considered separate, done for different reasons, but the pending trades of Arenado and Donovan were the two biggest items left on Bloom’s offseason agenda. Moving Arenado was about clearing out roster space and playing time for young players, namely Nolan Gorman and top prospect J.J. Wetherholt, baseball's No. 5 prospect. Moving Donovan is about getting significant young talent in return.

There are plenty of contenders who, now that Alex Bregman is off the free-agent market and Bo Bichette is presumably about to follow, will be very eager to acquire Donovan and his two remaining seasons of club control. Donovan, who turns 29 on Friday, can play multiple positions, hits the ball hard and consistently and is a clear team leader who would help anyone. The Mariners could offer the most, but the Red Sox -- a team Bloom has traded with twice already this offseason -- might need him even more if they miss out on Bichette. Either way: Donovan is next, and it's reasonable to suspect a move will happen soon.

4. It’s fun to dream on one more D-backs move (and two reunions)
Arenado’s best season in St. Louis was 2022, when he led the NL in WAR per both Baseball Reference and FanGraphs, slugging .533, winning his 10^th (and final) Gold Glove Award and finishing third in MVP voting. The player who finished first in the NL MVP race that season was none other than his then-Cardinals teammate Paul Goldschmidt, with whom he played for four seasons as one of the best corner-infield combinations in baseball.

Well, lo and behold, Goldschmidt -- one of the best players in Diamondbacks history -- is a free agent, and Arizona has an opening for a right-handed first baseman/DH. Could a reunion -- well, two reunions -- be in the cards for the D-backs?

5. Arenado’s tenure in St. Louis was a qualified success
After some rough losing seasons in Colorado, Arenado really did think he'd have a chance to reach a World Series with St. Louis. His best chance came in 2022, with him, Goldschmidt and a vintage Albert Pujols, who posted a 1.103 OPS in the second half of his final season. It didn’t work out -- and it should be said Arenado was a career 1-for-12 in three Cardinals postseason games -- but all told, Arenado was an undeniable positive for St. Louis in his five seasons, even if he faded toward the end.

He was, in many ways, the last of those Cardinals stars, someone who, when he likely makes the Hall of Fame (and presuming Yadier Molina does as well), will have continued the streak of St. Louis having a Hall of Famer on its roster every year since 2000. (If Mark McGwire ever makes it, that streak would go all the way back to 1914.)

But it also should be said that if Arenado goes into Cooperstown, he looks likely to go in as a Rockie, at least based on his career numbers. Arenado racked up 39.7 bWAR, 1,206 hits, 235 homers and eight Gold Glove Awards with Colorado, compared with 18.1 bWAR, 715 hits, 118 homers and two Gold Gloves in St. Louis. He had most of the best seasons of his career with Colorado and even slightly more postseason success there.

The Cardinals have been known for having stars. But with Arenado leaving … now their eyes turn to minting their next ones.