While the exciting signing, if it happens, would be another Designated Player or player requiring TAM money, there is a strong chance that the Seattle Sounders also acquire a player from within USA/Canada. They only have one international slot open right now, and in 2017 there are not a glut of international slots to acquire at low costs. No player is on the verge of getting a green card. They do have a lot of allocation money on hand, but spending it all severely limits the ability to build a 2018 roster.
With these thoughts in mind, let’s look through likely available options that would require light resources — something like a second round draft pick or the minimal amount of allocation money.