But that makes no sense, why would the Seahawks have to pay him after he signed with the Packers?

And he needed six weeks...

And Melton signed an ERFA contract, which you only get if you have LESS than 3 Accrued Seasons... and to avoid the waivers you need MORE than 3 Accrued Seasons.

So somehow, Melton went from 2 this off-season, to 4 before week 1.