The Seahawks signed Thomas from the practice squad to the active roster Wednesday, John Boyle of the team's official site reports.
Despite being signed to the practice squad, Thomas was elevated to the 53-man roster versus New England in Week 1 and Arizona in Week 2. In those two games, the 28-year-old accumulated four total tackles (three solo) and two passes defended while appearing in nearly all of Seattle's defensive snaps. With Ty Okada (hamstring) sidelined, Thomas could continue to see regular action for the foreseeable future.