The 44-year-old Testaverde, who was yanked for undrafted rookie Matt Moore in the fourth quarter of Sunday's 37-6 loss to Jacksonville, was given the day off.
"He doesn't have a particular injury or anything," Fox said. "Just the wearing of the game."
For the second time this week, Fox sidestepped whether Testaverde or Moore would start Sunday against the Seahawks.
"We'll evaluate that as the week goes on," Fox said.
Testaverde struggled against Jacksonville, completing only 13 of 28 passes for 84 yards and an interception.
Sunday was the sixth time in their last eight losses that the Panthers (5-8) have managed a touchdown or less. Jake Delhomme, who was lost to a season-ending elbow injury in Week 3, has as many touchdown passes (eight) as Carolina has had in the past 10 games.
Copyright 2007 by The Associated Press