GREEN BAY—Sam Shields knows he has no place to hide on Sunday, not with Calvin Johnson lined up across from him.

The fifth-year Packers cornerback also knows it’s his chance to continue his emergence as a big-name cover man, facing a four-time All-Pro receiver currently regarded as the best in the game. That’s the mentality he’ll take into Sunday’s game at Detroit, as the competitor about to compete to the max.

“You have to give it your all, your best, going against a guy like this, because if you don’t, he’ll torch you,” Shields said on Thursday. “He’ll embarrass you. Nobody wants to get embarrassed.”

Johnson has embarrassed plenty of defensive backs in his time, but on an otherwise awful day for the Packers, Shields held his own against Johnson last Thanksgiving.

It was the first time Shields was matched for the bulk of a game against him, and with six catches for 101 yards, Johnson got his share. But his longest gain came on a 20-yard touchdown grab against a botched zone coverage behind a blitz.

For the most part, Shields limited Johnson to slant catches in front of him, and he managed to outfight him on a jump ball in the end zone for an interception, no easy feat for a 5-11 corner against the 6-5 “Megatron.”

The spotlight will shine even brighter on Shields this time because he has entered 2014 with a new contract that pays him among the league’s elite corners. In his mind, this game isn’t about that, and it won’t feel any different getting ready in the Ford Field locker room on Sunday morning.

“You know what you’ve got on your hands,” Shields said. “You’ve been prepping all week. By Sunday, it’s time to play. You don’t have too much to think about.”

What he will think about is keeping Johnson in front of him as much as possible, like he did last November, to hopefully minimize the potentially game-changing plays.

“He’s going to get some catches. But my thing is, when he does catch it, don’t let him run after the catch,” Shields said. “Just get him down right there.”

The 240-pound Johnson isn’t easy to tackle, though.

“No, he’s not,” said fellow cornerback Tramon Williams, who has had his share of battles against Johnson over the years and has seen perfect coverages foiled. He called him physically the most difficult receiver in the league to bring down.

“He’s one of those guys where if you go high on him, you’ll probably fall right off him. So you have to kind of get down to his legs. But it’s not easy doing that either, because he has a good stiff arm.”

The Lions move Johnson around more now, lining him up outside as well as in the slot. The Packers haven’t revealed their game plan against him, but on the outside he’ll most likely face Shields, or possibly Davon House on occasion. In the slot, the matchup could be Williams, Micah Hyde or perhaps Casey Hayward, who is dealing with a glute strain but returned to practice on a limited basis Thursday.

Shields and Williams have the most experience against him, and Head Coach Mike McCarthy has seen him enough to know that trying to do anything special against him is only likely to backfire.

“It’s important for our guys, particularly our corners, to play with their technique and play with their leverage and just play football,” McCarthy said. “Anytime you go up against a top-notch player like Calvin, you can’t let players like that take you out of your technique.”

You can, though, let players like that test the limits of your ability, and that’s what Shields is looking forward to.

“A guy like that, you want that,” Shields said. “In the NFL, all eyes are on you, and everyone wants to see what you’re going to do against Calvin Johnson.”

ADDITIONAL COVERAGE - SEPT. 18