"Sage Rosenfels has a solution for the Vikings' four-quarterback dilemma.

"If I was the GM, I'd keep all four and pay us twice as much as what we're making," Rosenfels said Monday.

But the Vikings can't joke about a quarterback situation that might force arguably the most reliable backup option to Brett Favre out the door.

Rosenfels has outplayed Tarvaris Jackson during the exhibition season, but he's still the No. 3 quarterback on the depth chart. Coach Brad Childress said Monday "it'd probably be hard for it to change" based on the coaching staff's evaluations in practice.

No matter how well Rosenfels has played in three exhibition games — and he hasn't disappointed with 30-of-47 passing for 392 yards, four touchdowns and no interceptions, primarily against backups — the Vikings probably won't carry four quarterbacks into the season.

The Vikings need reliability behind Favre, who turns 41 in October and, despite starting 287 consecutive regular-season games — an NFL record for non-kickers or punters — is fresh off a third ankle surgery.

Complicating matters is rookie quarterback Joe Webb, who is talented, athletic and inexperienced. The Vikings could risk losing Webb if they push him through waivers before the regular season. Another team could snatch him up, as was the case with 2007 draft pick Tyler Thigpen.

That NFL teams rarely carry four quarterbacks has prompted speculation about whether Rosenfels will be traded or waived.

The Vikings play Denver in their exhibition finale Thursday in the Metrodome.

Favre told Sports Illustrated's Peter King that he received a lubricant injection in his ankle after his 16-for-26 performance for 187 yards on Saturday against Seattle.

Favre said the injection was "like a grease fitting" on an ankle that underwent an operation in late May to remove "a cup full of stuff — bone and all these other loose bodies."

"It's catching up with me, all this stuff," Favre told King.

Favre has had physical setbacks before, but he always suits up. Why stop now? Maybe the Vikings can take solace in his play-at-all-costs mentality, despite the occasional disclaimer about his health.

But if the ankle persists and blocking doesn't support him, the Vikings need a backup who can manage the game in his absence. "