How Much Pitching Can the Mariners Spare in a Gunnar Henderson Trade With the Orioles?

Who pitches on Gilbert’s day?

Aug 21, 2026; Baltimore, Maryland, USA; Baltimore Orioles shortstop Gunnar Henderson (2) makes a catch during the third inning against the Tampa Bay Rays at Oriole Park at Camden Yards. Mandatory Credit: Daniel Kucin Jr.-Imagn Images | IMAGN IMAGES via Reuters Connect

Trading Logan Gilbert for Gunnar Henderson solves one problem for Seattle and immediately creates another. That’s the part of this trade The Mariners would have to nail, because the fit on the dirt is an easy one.

Henderson could take over at shortstop after eight years of J.P. Crawford. If the Mariners want to give Colt Emerson that job, Henderson can slide over to third base. He’s played it in Baltimore and could fill the hole at the hot corner instead. Either way, we’d love to see a left-handed bat with 37-homer upside take aim at the right-field seats at T-Mobile Park. We’d also like to get through a road trip without asking the bullpen to cover too many innings because the rotation spot we traded away was never filled.

Ryan Divish and Adam Jude reported from the GM meetings that the Mariners are expected to check in on Henderson. One industry source described the perceived price as “exorbitant” and put the chances of Seattle meeting it very low. We’ve already made the case for picking up the phone. Now we can draw a hard line at where the Mariners should stop engaging.

The Mariners Can Spare a Starter Only if They Can Replace Him

Keep Bryan Woo and Bryce Miller out of it. We’d hear Baltimore out on George Kirby. Those extra years of club control ought to buy a lighter prospect package.

Logan Gilbert is a different conversation. Without an extension, he’s a year away from free agency. We’d talk about swapping that last season of Gilbert for two from Henderson.

He could potentially take the weight off a lineup that can come off relatively thin. But if Kirby or Gilbert is the price, Seattle needs to come out of the winter with another starter we’d trust against Houston in September. Otherwise we’ll spend all summer talking about the hole we opened to get the bat we wanted.

An Emerson Hancock offer would cost Seattle fewer proven innings, and that’s exactly why we’d expect Baltimore to ask for a much bigger prospect package. How far down our list of players we’d hate to lose are we willing to go just to keep Kirby and Gilbert in the rotation? Obviously we’d settle that before making the offer, but expect at least one top prospect in the mix. Don’t be surprised if the O’s try to pick Ryan Sloan and pair him with another top prospect bat.

Look at Coby Mayo. Both sides would struggle just to agree on a price for his upside while he’s still trying to stick in the majors. Now try putting a number on two years of a former MVP finalist, while both clubs have high valuations on the players they developed. The Taylor Ward deal tells us they can agree on a veteran outfielder for three relievers. Try getting them to agree on what an extra year of Kirby is worth. It won’t be an easy conversation.

Jason Kanzler Could Help Henderson Get a Big Payday

Henderson hit 37 homers and put up 8.8 bWAR in 2024. He slipped to 5.4 bWAR in 2025 and 3.2 in 2026. The 24 homers last season still catch your eye. So does the 101 OPS+, which puts his bat barely above league average. He’s still only 25. He has plenty of room to get back to being the guy pitchers hate seeing come up with two men on. The Mariners would have two seasons to see how much of that player comes back.

There’s real money riding on which Gunnar Henderson shows up over the next two seasons. He can hit free agency after 2028, and the guy who hit 37 homers in 2024 walks into a different market than the guy who posted a 101 OPS+ in 2026. If we get him now, Jason Kanzler and his staff get a full season to work with him before his contract year. Kanzler’s background in hitting instruction and player development could help.

We’d spare one proven starter for Gunnar Henderson, and only if the Mariners have a realistic way to replace him. Woo and Miller stay. We’d talk Gilbert without an extension, and we’d talk Kirby at a price that reflects his extra years of control. If Baltimore wants Kirby and a haul from the farm, we’re out. Hancock is the route that keeps the top of the rotation intact, but even that offer has a limit. We want Henderson’s bat in a pennant race. We want five starters we can trust when we get there, too.