Cardinals' Timing for Brendan Donovan-Mariners Swap Explained

The St. Louis Cardinals certainly are going to look a lot different by the time the 2026 Major League Baseball season kicks off in March.

When the Cardinals last took the field for a regular-season game, Sonny Gray was the team's ace, Nolan Arenado was firmly planted at third base, Willson Contreras took over first base and Brendan Donovan was at second base and earned his first All-Star nod in 2025.

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Now, all four are gone. Gray and Contreras are members of the Boston Red Sox, Arenado was dealt to the Arizona Diamondbacks and Donovan was sent to the Seattle Mariners in a three-team blockbuster. Donovan is the most recent member of the team to go and the Cardinals got a haul in return. The Cardinals received three high-end prospects plus two draft picks between the second and third rounds of the 2026 Major League Baseball Draft.

The Cardinals made a tough, but good move

Sep 15, 2025; St. Louis, Missouri, USA; St. Louis Cardinals second baseman Brendan Donovan (21) take his position against the Cincinnati Reds in the sixth inning at Busch Stadium. Mandatory Credit: Joe Puetz-Imagn Images | Joe Puetz-Imagn Images

On paper, it looks like a very good deal for the Cardinals. But why now? Donovan is just 29 years old and has two seasons of control before he is scheduled to hit the open market. After the deal got done on Monday, MLB.com's John Denton noted that part of the reason for the deal now was because the club believed that the team's window for contention could open after his cost-controlled years are up.

"Fearing that Brendan Donovan’s cost-controlled prime years could expire before their rebuild puts them in position to contend again, the Cardinals dealt the All-Star infielder-outfielder to the Mariners for three Minor League prospects and two Competitive Balance Round Draft picks in a three-team trade that also involved the Rays, the team announced Monday," Denton wrote.

"In return for the 29-year-old Donovan, the Cardinals received 22-year-old formerly ambidextrous pitcher Jurrangelo Cijntje (the Mariners' No. 7 prospect, per MLB Pipeline), 20-year-old free-swinging center fielder Tai Peete (Mariners' No. 11), 24-year-old outfielder Colton Ledbetter (Rays' No. 24) and the No. 68 and No. 72 picks in July’s MLB Draft."

The logic is sound. If the Cardinals don't think they're going to contend in 2026 or 2027, flipping Donovan now for a massive haul before his price tag likely skyrockets makes sense. It's tough to see him go, but if the Cardinals hit on a couple of these prospects, that will change things for the club in the long-term. For example, Cijntje is a top-100 prospect in the sport, per MLB.com. That's exciting and he hasn't made his big league debut yet. When he does, the Cardinals will have years of control. St. Louis has been stocking the farm system with pitchers all offseason.

Now, two of the team's top-eight prospects are starting pitching prospects that the club acquired this offseason (Cijntje and Brandon Clarke). These deals sting now, but if they work out, the club will have a handful of cost-controlled, young pieces for the long run. It would've been nice if Donovan could've been a part of the next successful run in St. Louis, but it sounds like the timeline didn't add up.

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