The cat that Leslie Frazier wanted to keep in the bag until Friday had already escaped on Wednesday. But the Vikings head coach did keep his promise of formally announcing his starting quarterback for Sunday's game at Dallas.

And, yes, it is indeed Christian Ponder.

Frazier went on to explain his decision and the delicate balance he walks between trying to win games while also wanting to make an educated assessment of quarterback Josh Freeman, who was signed on Oct. 6 and had one disastrous start after having only four days of practice with the first unit.

"We're in the business of winning games," Frazier said. "Christian gives us the best chance to win and that's how we're going to approach it. Now there may come a point where you have to make a decision for different reasons, but we're in a position right now where it's purely based on who gives us the best chance to win."

Ponder fell to 0-4 as a starter this year when he completed 14 of 21 passes for 145 yards, no touchdowns, no interceptions and an 86.4 passer rating in last week's 44-31 loss to the Packers. Matt Cassel served as the backup, but Freeman has been cleared from the concussion that sidelined him last week.

"I have not talked to the guys about the backup situation yet," said Frazier, who wouldn't announce his backup. "We're going to go through that [later Friday]."

No one is saying what the plan at quarterback will be next week, when the Vikings make a quick turnaround to play the Redskins at home on Thursday.

"I know that I have to perform to have myself stay on the field," Ponder said. "I don't know what the plan is after this week. Just like last week, my future ends after Sunday's game. I don't know what's going to happen after that."

No analysis

Frazier was asked how the Vikings could make an accurate assessment of Freeman if he isn't given more opportunities to start. In his only start, Freeman completed just 20 of 53 passes in a 23-7 loss to the Giants on Oct. 21.

"You're way ahead of me," Frazier said. "I'm only focusing on the Dallas Cowboys. Please, a win, just a win against the Cowboys. Then Coach Frazier will be able to look far ahead in that crystal ball and make some of those decisions, but a win against the Cowboys. And that's what I'm telling the team, the old cliché, one game at a time."

Shorthanded secondary

The Vikings made it official, ruling cornerback Chris Cook (hip) and strong safety Jamarca Sanford (groin) out because of injuries. With free safety Harrison Smith (turf toe) on injured reserve, that means three of the four opening-day starters in the secondary will not play against Tony Romo and the Cowboys' eighth-ranked passing attack. The only starter who will be on the field is cornerback Josh Robinson. Nickel back Xavier Rhodes also is healthy.

"We're a little thinned out back there, particularly at safety," Frazier said. "But we're going to end up starting Mistral [Raymond] and [Andrew] Sendejo and we'll work Robert Blanton in there. At corner, with Chris being out, we'll have to go through our rotation with Josh, Xavier, [Marcus] Sherels and A.J. [Jefferson] Those will be the guys, and we signed Shaun Prater a few weeks ago as well."

Also out for this game are tight end Rhett Ellison (ankle), nose tackle Fred Evans (knee) and running back Matt Asiata, who has a shoulder injury and also had to leave the team this week after his father was killed in a car accident on Monday.

Listed as probable for the Vikings were receiver Greg Jennings (knee), linebacker Chad Greenway (wrist), Jefferson (ankle), receiver Rodney Smith (hip), kicker Blair Walsh (hamstring), defensive tackle Kevin Williams (knee) and running back Adrian Peterson, who Frazier rested on Friday.

"That was more of my decision than anything going on with [Peterson] physically," Frazier said. "I want him to be ready to go on Sunday hoping that he'll get some carries."

Cook adjusts goal

Sunday's game will mark the 28th time that Cook hasn't been able to play because of injuries or legal issues since joining the team as a second-round draft pick in 2010. The number of games he's played also sits at 28.

"Yeah, I do feel like I have to put a string of games together," said Cook, who has never started more than 10 games in a season. "But I'll worry about that when that time comes."

Asked how frustrated he is by not being able to play for the second time in five games, Cook said, "Early in the week, I was real frustrated. I came in on Wednesday and everybody was like, `What's wrong with you? Why you so down and out?' I was just letting it bother me. But it's nothing that's season-ending or career-ending, so I just let it go and I'm moving on. I'm smiling now."

Four Cowboys out

The Cowboys ruled out cornerback Morris Claiborne (hamstring), linebacker DeVonte Holloman (neck), guard Brian Waters (elbow) and safety J.J. Wilcox (knee).

Listed as doubtful are defensive end DeMarcus Ware (thigh) and receiver Miles Austin (hamstring).