Nelson (knee) did not participate at the Seahawks' practice Thursday, John Boyle of the team's official site reports.
Nelson was listed as a limited participant at the team's walkthrough practice Wednesday, but he took a step backwards at the team's first official practice of the week. The offensive lineman made his Seattle debut in Monday night's loss to the Bears, and he appears to have picked up a knee injury in the contest. Nelson will have one more opportunity to return to practice before Sunday's contest against Arizona.