EDEN PRAIRIE, Minn. -- Minnesota quarterback Gus Frerotte is listed as doubtful for the Vikings Sunday against Arizona with a lower back injury.
Coach Brad Childress says Frerotte is improving and will continue to be evaluated on Saturday and Sunday.
"He's gotten incrementally better," Childress said. "It's not a leaps and bounds thing."
All signs point to Jackson being under center. He took all the snaps in practice this week and played very well in emergency duty last week against Detroit.
Kick returner Darius Reynaud is out because of a bad foot.
Allen leads the team with 12.5 sacks. He's played much of the season with a severely sprained shoulder and said he is hopeful he can play through this injury as well. Allen did not practice on Wednesday or Thursday this week, but did practice on a limited basis on Friday.
Allen said it was up to head athletic trainer Eric Sugarman and Childress to determine if he was ready to play, but he said they will have a hard time convincing him that he is not.
"It's almost an impossible task," Allen said. "But I have a lot of respect for those guys, so I do listen to their opinion. Sometimes you have to get an outside view."
Copyright 2008 by The Associated Press