The Cardinals (9-5) would be all but eliminated from postseason contention with a loss. A win for the Seahawks (12-2) will earn them home-field advantage throughout the playoffs.
The Cardinals, who earlier clinched their first winning season since 2009, wouldn't even ensure itself of a playoff spot with a win Sunday followed by a home victory over the San Francisco 49ers next week, though 11 wins would tie a franchise record. The 2008 New England Patriots are the only club during the 12-team format to miss the playoffs despite winning 11 games.
Palmer has recovered enough to play after suffering a low-grade, high left ankle sprain against the Tennessee Titans last Sunday. He was limited all week, though the quarterback's mobility wasn't an issue.
Fitzgerald was scheduled to see an independent neurologist for clearance to play after Friday's practice, before which he hadn't shown symptoms of a concussion he had suffered this past Sunday and Arizona's trainers allowed him to go through a full practice.
Safety Rashad Johnson (high ankle sprain) was the only Cardinals player listed as doubtful for Sunday's game. His status was still uncertain Sunday morning.
ESPN.com Cardinals reporter Josh Weinfuss and information from The Associated Press contributed to this report.