When Minnesota Vikings coach Brad Childress decided to rest Brett Favre and many starters for the preseason finale against Dallas on Friday night, it did anything but render the game meaningless.

Favre's arrival just more than two weeks ago stabilized the Vikings' quarterback situation in one respect, but threw it into upheaval in another.

Before Favre, quarterbacks Tarvaris Jackson and Sage Rosenfels were competing for the starting job while second-year player John David Booty was entrenched as the third-stringer and possibly the long-term solution for the position.

Now the future of all three is up in the air.

In all likelihood, Jackson, Rosenfels and Booty are competing for two roster spots. Favre played into the third quarter in the preseason game against Houston on Monday night, so all three will be looking to make an impression on Childress in their last chance against the Cowboys.

"Definitely," Jackson said. "You never know with this business period. I just take it as it is. Whatever happens, happens. I can't control it. I just try and get better, that's it."

Jackson is in his fourth year in this system and played very well against Kansas City two weeks ago. He threw for 202 yards and two touchdowns and had a perfect quarterback rating.

But because Favre played in the only series of the third quarter for the Vikings against Houston, Jackson played only one series in the fourth quarter. His strong performance against the Chiefs, coupled with being just 26, makes him perhaps the most likely of the three to be traded.

"I can't worry about it," Jackson said. "I'm not worried about it because I can't control it. Whatever is going to happen is going to happen, whether I worry or not."

Rosenfels was acquired in a trade from Houston before the Vikings signed Favre. In an instant, he went from having the opportunity to compete for the starting job for the first time in his nine-year NFL career to fighting for a roster spot.

Rosenfels missed the second game of the preseason with an ankle injury, but was sharp in his debut against the Colts on Aug. 14. He was 10 of 13 for 91 yards in that game.

"I think I've done a lot of good things while I'm in there and made very few mistakes," Rosenfels said. "That's half the battle as a quarterback is not making mistakes. I'm just trying to execute the offense and I think I've done a pretty good job with that."

In his return to Houston, Rosenfels completed both of his passes for 22 yards in his only meaningful series of the game. Booty did not play against Houston and has completed 10 of 15 passes for 84 yards in two exhibition games this year.

"I think all of those guys will have an opportunity to play and they will play more extensively than they have," Childress said.

Cowboys coach Wade Phillips is taking a similar approach with his starters _ most will play sparingly, if at all. That includes quarterback Tony Romo, who grew up as a Favre fan in Burlington, Wis., and running back Marion Barber, who starred at the University of Minnesota.

The last thing Phillips needs is another player getting hurt. Six of the Cowboys' 12 rookies have been injured in the preseason this year, including top pick Jason Williams (high ankle sprain) and safety Michael Hamlin (broken arm).

Linebacker Brandon Williams will miss the season with a torn knee ligament and the same is likely for tackle Robert Brewster (torn chest muscle).

"We know what Marion Barber's going to do, what Felix Jones and Romo and those guys are going to do, but it's unknown whether some of the other guys can help that group or not," Phillips said. "So we'll see what they do. It'll be a good challenge for them."

Houston at Tampa Bay

The Bucs will play their final preseason game one day after coach Raheem Morris fired offensive coordinator Jeff Jagodzinski. Unhappy with the passing game, Morris installed quarterbacks coach Greg Olson as the new offensive coordinator. Olson will get one dry run at calling plays against the Texans before Tampa Bay opens the regular season against Dallas on Sept. 13.

San Francisco at San Diego

LaDainian Tomlinson has had a busy preseason by his standards. But after starting the first two games of the exhibition season that he has traditionally skipped altogether, Tomlinson will not play in the finale against San Francisco. He also did not play last Saturday at Atlanta. Tomlinson wanted to play this preseason after rushing for a career low 1,110 yards last season. He had 12 carries for 28 yards in two preseason games.