CHICAGO -- There's no doubt Josh Robinson is more comfortable now as a third-year cornerback playing on the outside than he was during the Minnesota Vikings' failed experiment with him as the slot cornerback last season. But there is one reality of Robinson's move back outside that always seemed hard for him to escape: He is 5-foot-10. The receivers he'd cover on the outside would often be four or five inches taller -- or more.

The Vikings knew the Bears would be coming after Robinson in nickel situations on Sunday. Coach Mike Zimmer knew the Vikings would have their hands full dealing with 6-foot-3 Alshon Jeffery and 6-foot-4 Brandon Marshall.

He based his approach to covering the two Chicago Bears receivers on the reality that the Vikings often wouldn't be able to outjump them; "We've got to be great at pulling their hands apart," he said Thursday. "We've got to be great with putting our hands in what I call 'the hole' [between their hands]. Being in the right position, too, that helps."

Robinson often appeared to be in the right position on Sunday. But against a team that had singled him out for special treatment on Sunday, he got burned.

The Bears went after Robinson more than a dozen times on Sunday, with Jay Cutler throwing all three of his touchdown passes to Jeffery and Marshall on balls where it seemed Robinson could do little to make up for the receivers' stature. He was flagged for defensive pass interference on Jeffery's touchdown after the receiver worked through Robinson's arms on his way back to Cutler, shielding the ball with his body.

Marshall snatched a deep ball away from Robinson on the second touchdown, with safety Robert Blanton trailing in coverage. And on Marshall's final TD, he simply made like a power forward, calling for the ball before the play, posting up in the end zone and reaching for the ball after boxing out Robinson.

Between the TDs, there was a 34-yard pass that Jeffery took away from Robinson after it looked like the cornerback was in position for an interception. And at the end of the day, both the cornerback and the head coach seemed at a loss for what to do about it.

"I would have changed up some coverages," Zimmer said when asked what he could have done differently, before adding, "I can't make these guys taller."

Cutler's struggles this season have come largely against zone coverage, when he is frustrated by an inability to go down the field, and his worst throw of the day came on a blitz when the Vikings dropped defensive end Brian Robison back into coverage and safety Harrison Smith sat over the top of Martellus Bennett, waiting to make an interception.

But the Vikings rely primarily on man coverage, and as much as they like to move Smith around, keeping him back in a two-deep shell would have taken away part of the blitz package that's worked so well for them, in addition to exposing them to more damage from Matt Forte, who caught six passes for 58 yards.

Instead, they often relied on man coverage with a single safety deep and counted on their corners to play as well as they have in recent weeks. Against the Bears' taller receivers, Robinson, in particular, could only do so much.

"We played our normal defense," Robinson said. "Our defense relies on our corners to cover. We knew what they were going to do, and they came out doing exactly what we thought. In the end, I need to play better. That's the biggest thing I take from this game. You can't be in position and not make plays."