Vikings quarterback Jackson uncertain for next preseason game

"They have never been part of a training room culture, nor do they want to be."

Childress lauded Jackson for coming into training camp in great shape and his willingness to work with athletic trainer Eric Sugarman when rehab is necessary. If he can't go on Saturday, the 37-year-old Frerotte will take his place.

"I'm sure he's going to be fine," Frerotte said Monday. "Injuries happen. It's a part of football. He'll work hard to get back out, and he'll know when he's ready."

The Vikings signed Frerotte for this purpose. When Jackson was injured last season, they had to resort to veterans Kelly Holcomb and Brooks Bollinger, neither of whom proved to be reliable running the offense.

Now it could be the strong-armed Frerotte's turn to show he is an upgrade. He went 4-for-9 for 32 yards and a touchdown against the Ravens.

One major difference between the two is that Jackson is much more mobile, while Frerotte is the more classic drop-back passer.

Jackson scrambled twice for first downs against the Ravens, adding a dimension that demands the attention of the defense. But he was also injured when he didn't slide, which is something that no doubt will be addressed as Jackson returns to action.

"I think he understands the fact that he needs to get out there for 16 games this year," Childress said. "Maybe we learn to live to fight another day and take 2 less yards up the field."