Seattle doesn’t need a SS, but it’s probably the only infield position they have that doesn’t. Per Roster Resource, their 1b is a platoon of Luke Raley and Mitch Garver, their 2b is Dylan Moore, and their 3b is a platoon with Josh Rojas and Luis Urias.
They do have a prospect named Cole Young who will probably take over 2b at some point. But the other two positions leave room for improvement.
I think their primary target should be Coby Mayo, the Orioles’ top prospect (MLB.com overall #2) who has nowhere to play. But we will see if a deal can be worked out. It becomes much more likely if Seattle is willing to part with either Miller or Woo…