For Brad Childress, picking his starting quarterback this week might be the easiest decision he's made in Minnesota since choosing to keep that glorious windchill-repelling mustache.

In this corner is Gus Frerotte, a glacier-slow 37-year-old backup with a bad back who was last seen struggling against the Detroit Lions, the worst team in NFL history.

In this corner is Tarvaris Jackson, a healthy, fresh, 25-year-old drafted to be a starter who has just played his best six consecutive quarters since leaving Alabama State.

Childress played coy on Monday -- he probably holds the menu over his face in restaurants so the other diners can't out-order him -- but you need not worry. Despite approval ratings rivaling Rod Blagojevich's, Childress has managed a challenging quarterback situation flawlessly.

He started Jackson, which, after the Vikings failed to upgrade the position despite intensive tampering, represented his only real choice. The Vikings had to see what they had in Jackson and, after a mediocre performance in Green Bay, he proved unprepared for the job with an awful performance at home against a decimated Indianapolis team.

Childress, reading the body language in his locker room and correctly assuming the season and his job were on the line, took the risk of benching Jackson and starting Frerotte.

He made the change at the right time, and Frerotte exceeded expectations for a guy who considered retirement last winter.

Frerotte went 8-3 as a starter, with Jackson handing him one of those victories with a second-half comeback in Detroit.

Frerotte even displayed impeccable timing, getting hurt against Detroit and handing Jackson the best opportunity a doubt-ridden young quarterback could receive, the chance to rally a team to victory against, again, the worst team in NFL history.

Sunday, Jackson played his best game as a pro, throwing four touchdown passes -- three of them looking like they were guided by GPS -- and no interceptions in the Vikings' 35-14 reminder that the Arizona Cardinals remain the Arizona Cardinals.

You don't bench your young quarterback when he reaches his professional peak, and you don't return a slow, old guy with a bad back to the lineup with the season on the line.

This is an easy decision in the context of this season. It's an even easier decision in the context of this team's future.

Frerotte plays with admirable gumption, but at best he'll return as a backup next season. Jackson, given the unpredictability of young quarterbacks in this league, could at least become a high-quality backup next year, perhaps even become the starter the Vikings envisioned all along.

We still don't know if Jackson can win a game with his arm against a good team capable of neutralizing Adrian Peterson, but then trying to categorize or analyze Jackson's success is probably a mistake in a league where matchups and emotions cause performances to fluctuate weekly.

Right now, it doesn't matter whether Jackson winds up starting for the Vikings next season or whether the Cardinals game will someday be viewed as his professional apex or launching pad.

What matters now is that Jackson is the quarterback who is best-equipped to win the Vikings' next game, and in a week-to-week league, that's all that matters.

Childress doesn't have to analyze any flow charts or look for deeper meaning in Jackson's latest performance to make this decision. The right call this week is as plain as the mustache on his face.

Jim Souhan can be heard Sundays from 10 a.m.-noon on AM-1500 KSTP.

Tarvaris Jackson has thrown five TD passes in his past six quarters of play. Associated Press