Mariners acquire TJ Friedl, Spencer Steer, and Alexis Diaz for Logan Gilbert
Let's get this straight, the Mariners should not trade Gilbert unless they get an absolute haul! This could very well be it. This addresses pretty much every need the Mariners have. A legit outfield bat, a high upside bat, that can play 5 different positions on the field, and gives them another high leverage bullpen arm. All while, maintaining years of control. Friedl and Steer are both under control through 2029, while Diaz is under club control through 2028.
As the roster currently sits, Friedl is your starting right fielder and Steer is your starting DH. In some form your lineup could go, JP, Julio, Friedl, Steer, Cal, Geno, Kelenic, France, and Rojas. That is vastly improved from the lineup they trotted out last year with Dylan Moore, Sam Haggerty, and Jose Caballero. Trading Gilbert would really hurt, but it still gives you a rotation of Castillo, Kirby, Miller, Woo and the 5th spot is a spot that you might have to fill in free agency, if Hancock or Marco aren't ready.
This trade is a hard price to pay for the Reds, but given their depth in the outfield and infield, it could make some sense. They might be hesitant to part with this much, but getting an elite arm like Gilbert, who is under club control through 2028, is going to be very expensive. Gilbert was among the best pitchers in baseball this year and was probably the most consistent Mariner's starter. The homers bit him a little bit, but there is the potential to be one of the best #2's in baseball or the #1 on a lot of staffs in baseball.