Movember was long gone, yet here came Matt Cassel still sporting his Fu Manchu mustache. Underneath it was the kind of smile you'd expect from a guy who had just been named the Vikings' starting quarterback for Sunday's game at Baltimore.

"I told my wife, 'You can never shave after a win,' " Cassel said Wednesday. "She told me she's going to [shave] me in the middle of the night. So we'll see what happens here over the next week."

Waiting to see what happens at quarterback from week to week has become an all-too-familiar theme for the Vikings. For the fourth time in 13 games, they switched starters Wednesday when Christian Ponder experienced more concussion-like symptoms from the injury that knocked him out of Sunday's 23-20 overtime victory against the Bears.

Cassel's facial-hair superstition and Ponder's ineffective first half against the Bears notwithstanding, the starter a week from Sunday against the Eagles at Mall of America Field is, per usual, to be determined.

"Well, you're always graded on performance," Vikings coach Leslie Frazier said. "So if [Cassel] performs, we'll sit down and talk about it Monday and make a determination from there."

When Ponder broke a rib against the Browns in Week 3, Cassel started Week 4 against the Steelers. He passed for two touchdowns in a turnover-free victory and kept the job. But he lost it to Josh Freeman a week later after throwing two interceptions in a 35-10 loss to Carolina.

Vikings head coach Leslie Frazier said quarterback Christian Ponder hasn't passed concussion tests and Matt Cassel is expected to start on Sunday against the Baltimore Ravens.
Video (01:31): Cassel: 'It's a one-week season'

Freeman's only action as a Viking came during his lone start at the Giants on Oct. 21, 14 days after he was signed. He completed only 20 of 53 passes (37.7 percent) in a nightmarish performance as the Vikings lost 23-7 and didn't score a point offensively.

Freeman suffered a concussion in that game and, to the angst of Vikings fans, hasn't played since. Talking about his upcoming No. 2 role in Baltimore, Freeman tried to help explain to reporters why he hasn't seen the field since the Giants game.

"An NFL offense — and I know you guys haven't been around them — but they're pretty complex," he said. "There are different layers. There's stuff that they might've run earlier in the year that's a pretty hard concept that they just installed for the certain week. There's a lot to take in, and it's been fun learning it.

"Of course, as a competitor I want to play. But I'm a guy that's just going to work my butt off until that opportunity comes."

Frazier has struggled while tiptoeing the thin line between supporting whichever quarterback is No. 1 at the time and maintaining a consistent message about the position. For example, earlier this season, he said only Ponder and Freeman were competing for the starting position, while Cassel would remain a backup. Obviously, like a lot of things, that's changed.

"Part of it is what he did in the second half of that ballgame on Sunday," said Frazier, referring to Cassel, who looked sharp while leading the Vikings back from a 20-10 deficit with a fourth-quarter touchdown pass and a last-minute, game-tying field goal drive.

"Also, seeing [Cassel's] comfort level with where we are, and having a comfort level with him, as well. But his work on Sunday has a lot to do with it. He did an outstanding job."

Frazier described Cassel as a pro for the way he handled his benching earlier in the season. Cassel said it's just part of the job.

"You only get as frustrated as you let yourself get frustrated," Cassel said. "Each and every day I've tried to work hard, I've tried to stay in the right mind frame because I think anything other than that it takes away from doing your job."