The Mariners can get bent, imo.
Over the last 3 years, Castillo is pretty comparable to guys like Jordan Montgomery when he hit FA and Nathan Eovaldi. Montgomery ended up with a 2 year deal at just under $24M. Eovaldi just got $25M. Castillo is owed $24M for 3 years with a potential 4th year at $25M. He gives you more innings than Eovaldi so maybe he gets slightly more, but he's not worth the $27M that Fried got. So how much is Castillo saving you vs the market? $1.5-2M/yr? I'm not giving up anything worth a horsefeathers for that and the Mariners are asking for a haul because its "plan Z."