Seattle designated Rhattigan (knee) to return from the reserve/PUP list Tuesday, John Boyle of the Seahawks' official site reports.
Rhattigan has yet to play this season while rehabbing from a torn ACL he suffered last December. With the move, Seattle opens a 21-day window for the special-teamer to be added to the active roster, but if he isn't, he'll revert to IR for the remainder of the campaign.