Freeman made his debut in a 23-7 loss to the previously winless New York Giants on Monday night, completing only 20 of 53 passes for 190 yards with no touchdowns and one interception.
Frazier said that Freeman, who showed no signs of sustaining a concussion during the game, was not feeling well Tuesday. "They're going to take him through the NFL protocol, and we'll evaluate him daily," Frazier said.
Ponder has not started since injuring a rib in a 31-27 loss to the Cleveland Browns on Sept. 22. Backup Matt Cassel took over as the starter until Freeman was signed on Oct. 6, three days after he had been released by the Tampa Bay Buccaneers.
"Looking at the history of guys who have concussions on a short week that are able to at least get cleared for Sundays, we'll have to proceed as if he's not going to make it," Frazier said of Freeman.
"We're going to need a good game out of our quarterback. We're focused on Christian having the best game of his career on Sunday night."
Frazier, who was heavily criticized for rushing Freeman into the lineup, said he understands the need for continuity at quarterback.
"That quarterback job, you want to be knowing who is going to be in the lineup week in and week out," Frazier said. "That's the situation where we are. Christian will do a good job for us Sunday night."
Wire service and Internet reports contributed to this story.