The Minnesota Vikings traded away their only real insurance at the game's most important position Friday night, a reckless and vindictive move that indisputably weakened the team in order to avoid the appearance of impropriety on the depth chart.

Sage Rosenfels was traded even though he was Minnesota's best backup at quarterback. AP Photo/Tony Avelar

I haven't always praised Sage Rosenfels during his two year-career with the Vikings, but this preseason he proved to be the Vikings' only competent backup behind Brett Favre. He far outperformed Tarvaris Jackson, who apparently has a tenured position unaffected by his performance. What anyone wouldn't give for the kind of job security he has.

Let's be perfectly clear: Rosenfels was traded Friday night to the New York Giants because he beat out Jackson for the No. 2 job. As crazy as it sounds, that's what happened. The problem was that coach Brad Childress long ago chose Jackson as his No. 2 quarterback and still hasn't given up on his prospects as a long-term starter. Childress never embraced Rosenfels' acquisition in March 2009, a move orchestrated not by him but by vice president of player personnel Rick Spielman, and inexplicably banished him to the bottom of the depth chart.

Rosenfels hasn't always practiced well, but his 111.7 passer rating this preseason was more than twice that of Jackson. But no matter how sloppy and inaccurate Jackson was, nothing would change Childress' mind. He said last week that he had seen what he needed to see in practice, and my understanding is he made it clear within the organization that under no circumstances would Rosenfels make the final 53-man roster.

Instead, the Vikings seem poised to keep rookie Joe Webb as their No. 3. Webb showed flashes of elite athleticism during the preseason but is in no way capable of taking over an NFL team with playoff aspirations. It's fair to wonder the same about Jackson, but trading Rosenfels allowed the organization to get some level of return -- one draft pick in 2011 and perhaps a conditional pick in 2012 -- and eliminate the uncomfortable dynamic of an upside-down depth chart.

Favre hasn't missed a start in 19 years, so much of this conversation could be moot. But trading away players because they outperformed underachieving (but favored) incumbents is no way to build a team. At least, not in my book.

Note: Surprisingly, the trade also sent kick returner/running back Darius Reynaud to the Giants. I wonder if that means Percy Harvin will resume his role as a kickoff returner. I have no idea who will return punts, although cornerback Asher Allen did get some work there in the preseason.