Moore got the call after 44-year-old Vinny Testaverde was among the Panthers' inactive players. Testaverde did not practice all week due to what coach John Fox called general soreness.
David Carr, who has been ineffective this season, was listed as the No. 2 quarterback.
Moore, who played at UCLA and Oregon State, was undrafted before signing with Dallas. He was one of the Cowboys' final cuts before the season and was signed by the Panthers two days later.
Because of numerous injuries, Moore played briefly in six games before Sunday. He had completed only 14 of 32 passes for 166 yards and three interceptions and a passer rating of 21.1.
The Panthers' quarterback situation has been in disarray since Jake Delhomme was lost to a season-ending right elbow injury in Week 3.
Seahawks safety Brian Russell (abdomen) was active despite missing two practices during the week.