Technically speaking, Vikings cornerback Chris Cook's season didn't necessarily end with him breaking his right arm in the third quarter of Thursday night's loss to Tampa Bay.

Yes, he was placed on injured reserve on Friday. Yes, he'll have surgery soon. Yes, the team will work out available corners on Saturday and likely have one signed by Monday. But Cook also was designated as the one Vikings player on injured reserve who can return to practice after six weeks and begin playing after eight weeks.

For those counting at home, the Vikings (5-3) have only eight games left. So Cook's shot rests on the Vikings making the, um, playoffs!?

"Yes," coach Leslie Frazier said, "That would be the only way."

It's an understandable transaction designation. First of all, Frazier said Cook's recovery time table is seven to eight weeks. Secondly, the top six teams in each conference make the playoffs and the Vikings (5-3) currently hold the fifth seed.

Of course, maintaining that status while facing a rugged remaining schedule without their blossoming 6-2 cover corner would be unlikely -- to say the least -- after Thursday night's stinker at Mall of America Field. In their final eight games, the Vikings face five of the top 21 current leaders in receiving yards, including Chicago's Brandon Marshall and Green Bay's Jordy Nelson and Randall Cobb twice apiece. You can also throw in Green Bay's James Jones and his seven touchdowns two times as well.

"Everybody has injuries," Frazier said. "So someone else will have to step up and make those plays for us."

That's become a common theme during Cook's three-year career. He lost 10 games because of injuries as a rookie and 10 last season facing, and eventually being acquitted of, a felony domestic assault charge.

"He's distraught," Frazier said. "It's tough. It's tough. He was doing well."

Without Cook, the Vikings will start rookie Josh Robinson at right corner. He's one of the fastest players in the league, but he's also 4 inches shorter than Cook.

A.J. Jefferson moves from dime back to nickel back. He's 6-1 and fluid, but he's only been in this defense since being acquired in a trade with Arizona on Sept. 1.

"We've been working [extra] with him from the time we got him for occasions like this," Frazier said. "He'll have to be ready now. We have an extra day or so to help him. But he'll have to play and probably play a lot."

The dime back after Cook went down on Thursday was punt returner Marcus Sherels. But Frazier said that could change to second-year pro Brandon Burton, who wasn't active for the Tampa Bay game. Either choice is a step down that's reminiscent of last season when the Vikings were forced to play during what became an embarrassing season for the secondary.

If the fourth quarter was a glimpse of life without Cook the rest of this season, the Vikings are in trouble. The Bucs entered the game ranked 30th in third-down conversions (29.2 percent). Yet they converted four third-and-long situations via the pass during an 87-yard, 16-play touchdown drive that crushed the Vikings' hopes of a comeback.

Here's a look at those four plays:

• Third-and-6 from the Tampa Bay 23: With the Vikings in their dime package, receiver Vincent Jackson is matched up against Sherels in the left slot. Jackson turns Sherels inside, cuts outside and makes the easiest 14-yard catch you'll ever see.

• Third-and-10 from the Tampa Bay 37: With the Vikings in their nickel package, receiver Tiquan Underwood is matched up against Winfield in the right slot. Winfield reads quarterback Josh Freeman's eyes and cheats to the left. Underwood breaks the other way just enough to catch a 12-yard pass.

• Third-and-10 from the Tampa Bay 49: With the Vikings in their nickel, Jefferson is at right corner. He has tight deep coverage against Mike Williams, but Freeman makes a great throw and Jefferson is a hair off in timing his jump as Williams makes a great catch for a 34-yard gain.

• Third-and-nine from the Vikings 16: Desperate to get off the field, the Vikings stay in their base defense and have safety Jamarca Sanford play press coverage on the left slot receiver. Williams is matched against Robinson on the other side. Williams runs a simple slant. Playing too soft, Robinson backpedals and loses his footing when he tries to break on the ball. Williams gains 11 yards.

NFL Network game analyst Mike Mayock might have foreshadowed the biggest challenge facing the Vikings over the next eight weeks when he made this observation after Jackson beat Sherels on that first third-down conversion.

"That's just stealing," Mayock said. "But that's what happens when you lose some depth in your secondary. That's a mismatch."