Gus Frerotte had hoped he might be able to make a quick recovery from a lower-back injury, but it's clear now that he won't be the starter.

Vikings running back Chester Taylor told WCCO that Jackson would start.

Frerotte, who did not practice Wednesday, said without hesitation after practice that he does not have a fracture in his lower back and that he's dealing with some "muscle stuff." Frerotte worked out in the pool and is trying to work his way back while giving his back a chance to heal.

Frerotte was injured while making a tackle after his second interception in the first half Sunday at Detroit.

"I just twisted in a weird way," Frerotte said. "I was kind of upset at the way it happened, and so I was trying to rip the ball out. I twisted him down. Something just popped, and I knew it right away."

Frerotte described his status as day to day. Jackson took the snaps in practice Wednesday in place of Frerotte, with rookie John David Booty serving as the backup.

Frerotte said he was happy that Jackson played well in relief Sunday. Jackson completed 8 of 10 passes for 105 yards with the go-ahead touchdown and no interceptions.

"I was so happy for him," Frerotte said. "I was really excited for him. ... You have to stick with it, it's a long season, and I was really proud and happy for him that he went out and played so well. He was the reason we won, and I was really excited to see him get back out there.

"Sometimes it's just good (when) as a backup you go out there (and) you don't think about anything. You just go play and let all your natural abilities take over."

Childress re-emphasized that he doesn't feel he will need to sign another quarterback to serve as the backup if Frerotte can't play.

"Right now I'd say J.D. is enough up to speed," Childress said of Booty. "The question would be: Could you get someone else up to speed? Are they in shape? Those kinds of things."

Frerotte said he's not sure how much practice time he would need to be ready to play. He said he's still studying the game plan and preparing as usual for the Cardinals.

"Obviously, I think you've got to get a little bit in," he said. "Every team is different. I know when I was with coach (Nick) Saban (in Miami), if you weren't on the field at all that week you weren't allowed to play. And then I was with other coaches where as long as you were able to go on Sunday you could play."