The Vikings traded Rosenfels to the New York Giants on Friday night. Rosenfels threw for 310 yards and three TDs in the preseason opener against St. Louis, but was just 8 for 17 for 92 yards with one TD in the next three games combined.
Rosenfels had the better statistics in the preseason, but Childress says Jackson has been better in practice and is the guy who would give the Vikings the best chance to win if Favre went down.
Jackson took most of his snaps this preseason with the starting offense and played against the opposing team's starting defense while Rosenfels always entered the game with the second team, an important difference, according to Childress.
"It's a completely different set of circumstances," Childress said. "I would hope that if Tarvaris was in there going with the twos, that he would have been able to light it up that same way."
Primary return man Darius Reynaud also went to the Giants in that trade, and Childress said Percy Harvin will be the team's kick returner when they open at New Orleans on Thursday night. Bernard Berrian and Greg Camarillo will split punt return duties.
The coach says the team is not interested in free agent receiver T.J. Houshmandzadeh.
The rematch of last season's NFC title game has revived talks over the hits Favre took in the loss to the Saints.
"I'd be more prone to see if we could find a younger guy or somebody that's been around in a West Coast offense," he said.
The Vikings say some of the hits Favre absorbed were illegal and should have been penalized. The Saints say they'll be just as aggressive when the two teams kick off the regular season on Thursday night.
But Favre downplays the punishment he took. He said Sunday he felt worse after a victory in Week 3 over the San Francisco 49ers than he did after the loss to the Saints in the Superdome.
"All the other hits, believe it or not, didn't really hurt," Favre said. "Did they take their toll over time? Sure they did. ... It might be the same thing [on Thursday night]. Who knows? It might be different. I'm not worried about it."
Favre says hits like those are just part of playing football.
Childress has said on more than one occasion that he thought some of the hits were dirty.
"I understand a quarterback's going to get hit, people are going to get hit," Childress said Sunday. "It's football. I don't have any illusions about that. What I hate to see are late hits or attempts to hurt anybody. I don't think there's a place for that in the game."
As many times as he was hit, Favre still managed to deliver a solid performance. He was 28-for-46 for 310 yards with one touchdown and two interceptions, the last one coming in New Orleans territory at the end of regulation.
"There's always a risk-reward, regardless of what side of the ball you're on by being aggressive," Favre said. "It's not like we were shut down offensively. We went into a hostile environment and were extremely productive on offense but yet it proved costly [with] the turnovers. So do I think we'll face the same style of defense this week? Sure."
Defensive coordinator Gregg Willliams and the Saints haven't been bashful this offseason about saying they aren't planning to change their approach for Thursday night's season opener.
Saints coach Sean Payton also defended his defense on Sunday.
"I think that we play with an attitude and a swagger and a confidence level that is within the rules and I like the way we play," Payton said.
Information from The Associated Press contributed to this story.