The Vikings rank last in the NFL in pass defense, allowing 326 yards per game. They are tied for first in touchdown passes allowed with 10.

In Sunday's 34-27 victory against Pittsburgh in London, the Vikings two best corners were rookie Xavier Rhodes and Marcus Sherels, who made the team primarily as a punt returner.

Chris Cook did not play because of a groin injury, Josh Robinson continued to struggle and A.J. Jefferson got zero snaps on defense, playing strictly on special teams.

Their cornerback situation is a mess right now and you wonder if Leslie Frazier and his staff won't use the bye to consider personnel changes.

Many fans would welcome the return of Antoin Winfield. Short of that, one logical move would be to replace Robinson with Rhodes as the starter at left cornerback, and possibly slide Sherels into that slot/nickel role.

Rhodes has been the team's best corner through four games. But in Cook's absence, Frazier's staff has resisted moving Rhodes to the right side. Instead, they started Sherels at right cornerback against Pittsburgh with Robinson starting on the left side.

Even if Cook returns next week against Carolina, you wonder how long the coacing staff will stick with Robinson. Until this point, Frazier has said he prefers to keep Rhodes as the outside corner in the nickel package, noting that Rhodes gets plenty of snaps because the Vikings use their nickel so often.

Rhodes has played in 71 percent of the team's snaps this season. But Robinson looks lost right now. According to Pro Football Focus, he has allowed 91.9 percent of passes thrown his direction to be completed for 377 yards.

Robinson also was called for a 48-yard pass interference penalty on Pittsburgh's opening drive of the second half that gave the Steelers the ball at the 1-yard line.

"He's had some struggles, in particular inside playing the nickel position," Frazier said. "That's been a challenge for him with all the things we ask that position to do. He's had some good moments and he's had some moments I'm sure he looks back at the end of the four weeks and said, 'Man, I can do that better,' and we think he will. We knew going in this offseason and even in training camp that there were going to be some moments that we would have to work through and we're experiencing some of that, but he's doing some good things as well."

Frazier was asked if the staff will consider moving Rhodes into the starting lineup because of Robinson's struggles.

"Xavier is doing some good things," Frazier said. "He is playing a lot in our nickel package which almost equates to being a starter with the number of snaps you get. We'll see how he continues to progress. Josh has had some ups and downs, but we think he's going to get better. We'll evaluate that coming out of the bye as well."

Rhodes made a mistake on Pittsburgh's final drive. He went for an interception on a pass to Jerricho Cotchery and missed, which led to a 36-yard catch and run.

"If he makes that play the game is over," Frazier said. "I like the aggressiveness. We worked on that play, he anticipated, he was there and came up a little bit short. You like to believe if we're in that situation again, as he gains more experience, he's going to make that play. You don't want to stifle that aggressiveness at the corner. The fact that he had enough gumption to go try it, that's a good thing. But if you don't make the interception, you have to make the tackle. You can't do both. But he'll learn from it and fortunately we survived it. That's part of some youth in the secondary."