I want you to sit for a minute and think about what Right Field looked like this year for the Mariners. The majority of it was played by Teoscar Hernandez, who has a good arm... and not much else to bring on defense. He doesn't take good routes, doesn't read it off the bat well, can't cover much ground, and has even admitted that he doesn't like running hard. He's got a great bat and good arm, and that's it. I do like the guy, but why not take advantage of the offseason and look for an upgrade.
That's where I think the Washington Nationals could possibly come into play as a partner for the Mariners. It doesn't look like Washington is going to be competing anytime soon, unless they grab a couple of big names in FA.
Could the Mariners and Nationals agree to a deal on someone like Lane Thomas? He still has a couple of years of arbitration left, and will become a Free Agent after the 2025 season, when he will be entering his age-30 season. He won't be old, by any means, but as someone who has turned the corner at 30, would Washington rather trade him away to keep building for the future? It seems like a reasonable thought to me.
I also think about it this way. What kind of deal would Thomas be worth in FA? Benintendi got 5/75, and I think Thomas gets more than that as a good defender (GG finalist currently) and a good mix of contact, speed, and power, as evidenced by his 2023 line of .268/.315/.468 with 28 HR, 20 SB, and 36 2B. Could he push to that $20 per season? Probably. He's a much different player, but let's say he gets the 5YR/$100M that Castellanos got. Add around $7M and $13M in the next two years of arbitration, and you get 7YR/$120M for a 3-4 WAR player per season... a number that might grow when he is in a more dangerous lineup.
I wanted to look at a couple of different deals that they could send out for Lane Thomas. A hitting focused package, a pitching focused package, and then the best deal i think they could offer which might be more than you want to see leave. Baseball Trade Values has a pretty low mark (10) for Thomas, so I'll bump that up a bit. They are accurate most of the time, but that one seems like it needs an adjustment after this season. This is also why you need to be careful with it.
Mariners Send: Sam Haggerty (7.1) and Alberto Rodriguez (2.5)
Nationals Send: Lane Thomas (10)
The Mariners would do that 100 out of 100 times, and they would drive both guys to the airport. Nothing against them, but you do that in a heartbeat if you get Thomas back. Let's try and find something more reasonable, and start with some hitters.