NFL coaches emphasize the third exhibition game as the last real tuneup for the first-stringers before the regular season begins, but the Vikings need to be cautious with Jackson's sprained right knee. He was hurt last week at Baltimore.
He warmed up his arm before the game, but wore shorts and a baseball cap while the rest of the team went through drills.
"I maybe could've played," Jackson said. "I'm just trying to be precautionary right now, not trying to go out there and push it."
"In fact he could've played and he could've played a certain way with a certain menu of plays and probably had to stay in the pocket, but that's not the prudent thing to do," Childress said. "There may be a time when he has to play the game that way, but I thought he did a good job of pushing to that and he'll get better as we go along."
Gus Frerotte started in Jackson's place and was 13-for-19 for 133 yards and an interception in the 12-10 loss.
Rice has fought a virus the last few weeks and has not practiced much. Berrian is bothered by a sore toe.
Copyright 2008 by The Associated Press