Grading the Mariners' blockbuster Brendan Donovan trade with Cardinals, Rays

After dancing around each other for months and months (and months), the Seattle Mariners and St. Louis Cardinals finally hooked up on a trade involving Brendan Donovan on Monday. For kicks, the Tampa Bay Rays got involved to make it a three-team deal.

Per various sources, the full deal breaks down like so:

• Mariners get: INF/OF Brendan Donovan (from STL)
• Cardinals get: RHP/LHP Jurrangelo Cijntje (from SEA), INF/OF Tai Peete (from SEA), OF Colton Ledbetter (from TBR), two Competitive Balance Round B picks (from SEA and TBR)
• Rays get: 3B Ben Williamson (from SEA)

That it's the Mariners who ended up winning the Donovan trade sweepstakes should come as a surprise to nobody. They were always the strongest suitor for him on paper, and they seemed to have the market to themselves coming into this week. The San Francisco Giants took themselves out of the running by signing Luis Arraez, while the Boston Red Sox had seemingly turned their attention to other options.

Grading the Mariners, Cardinals and Rays' returns in the Brendan Donovan trade

Now that the trade has finally been made and various elements of it are public, the natural question is how all three teams involved in it made out. Here's how we'd grade the returns for each club:

Mariners grade: A-

Cardinals grade: B-

Rays grade: B

The short version for the Mariners is that they got a player they very much needed, and without having to give up any can't-miss pieces for the future. The Cardinals will instead roll the dice on two high-upside prospects who nonetheless carry question marks. The Rays, meanwhile, seem to have seen a chance to pick up a spare part and took it.

Explaining the Mariners' A- grade

In Donovan, the Mariners are getting a versatile defender who was an All-Star in 2025, and who's still on the good side of 30 years old (29) and under club control through 2027.

Donovan's bat alone promises to be a substantial upgrade for Seattle's everyday lineup in 2026. He's an excellent bat-to-ball hitter with a decent ability to draw walks, which have thus far served as the two primary pillars of a career .361 OBP. The Mariners badly needed a guy like that in the leadoff spot last year, as it was a revolving door that ultimately posted a mere .311 OBP.

Defensively speaking, Donovan is a Gold Glove winner who fits best at second base, where the Mariners had been facing uncertainty following the loss of Jorge Polanco to free agency. Per Adam Jude of The Seattle Times, the Mariners also see him as a viable third baseman:

This is significant, as it implies the Mariners are ready to be flexible with Donovan's everyday role coming out of spring training. It seems possible that he'll play whatever position Cole Young or Colt Emerson doesn't earn. If both perform well enough to deserve starting nods, it's even conceivable that Donovan will be used as a super-utility man off the bench.

In Cijntje and Peete, the Mariners gave up first-round draft picks from 2023 and 2024, respectively. That hurts in the abstract, but neither is a sure thing even by prospect standards. Peete's stock has fallen precipitously since 2023, while Cijntje had just been stripped of his "switch-pitcher" status by the Mariners before Monday's trade.

As for Williamson, he simply wasn't going to be needed after Donovan came aboard. Not having him around as a depth option in the minors isn't ideal, but flipping him to Tampa Bay to close the deal feels like an acceptable cost of doing business.

Explaining the Cardinals' B- grade

This might seem harsh, but sometimes you just have to call a team out for setting high expectations before eventually settling for a more modest reality.

The Cardinals reportedly viewed Donovan as a star-caliber player in trade talks, which differed from how other clubs perceived him. Setting the bar high was nonetheless the Cardinals prerogative, of course, and one of the Mariners prospects whose name surfaced in rumors was Lazaro Montes.

Had the Cardinals gotten Montes, they would have scored MLB Pipeline's No. 43 prospect for 2026. While there are questions relating to his swing-and-miss offensive profile and iffy defensive outlook, his power is one of the more notable carrying tools among all prospects.

In Cijntje, the Cardinals instead scored MLB Pipeline's No. 91 prospect. That's still good, but the question looming over the Netherlands native is what, exactly, he is.

He was nominally a switch-pitcher in 2025, but one who got tuned up by minor league hitters for an OPS over 1.000 by both lefty and righty batters when pitching lefty. His right arm is his better asset, but an .845 OPS in right-on-left matchups raises the question of whether he'll have a fatal flaw even if the Cardinals continue the Mariners' mission to transition him to righty-only pitching.

As for the other two prospects in the trade, both Peete and Ledbetter have reached a "prove it" phase in their pro careers. Peete just hasn't hit as a pro, and least of all as he managed only a .692 OPS for High-A Everett in 2025. Ledbetter only had a .716 OPS for Double-A Montgomery.

The competitive balance picks are the Cardinals' potential ace in the hole here. They got the No. 68 pick in the 2026 draft from the Mariners, and the No. 72 pick from the Rays. Players chosen in those spots include John Lackey, Daulton Varsho, Dan Haren and Charlie Blackmon.

Ultimately, this trade feels like quantity over quality for the Cardinals. While far from a total defeat, you do wonder if they might have done better if they hadn't waited until Donovan had only one practical suitor before finally going ahead with a trade.

Explaining the Rays' B grade

The Mariners spent much of the winter signaling that third base would be up for grabs between Williamson and Emerson this spring. But as this trade makes clear, Williamson wasn't so much the de facto favorite as in Emerson's way.

Unfortunately for the 25-year-old Williamson, he doesn't have a clearer avenue to everyday playing time in the majors with the Rays. The best thing he has going for him is Gold Glove-caliber defense as a third baseman, but he can look up the depth chart and see 45-homer slugger Junior Caminero at the hot corner.

The Rays could look to transition Williamson into a role as a super-utility man, and he might just have the athleticism to pull that off. Or, they could stash him in the minors and hope that his bat makes the case for a more substantial role.

There's a non-zero chance of that happening, given that Williamson finished his 2025 season by slashing .327/.417/.510 in two months with Triple-A Tacoma. That apparently had to do with [waves hands] swing adjustments after he had hit only one home run in 295 plate appearances as a Mariner.

Either way, the Rays have a higher likelihood of getting something out of Williamson than they did of getting anything out of Ledbetter and the comp pick. He's exactly the kind of low-stakes lottery ticket the Rays love to take on, and often have good luck with.