ALLEN PARK, Mich. -- Imagine this. You were the best athlete in your high school. Then you were a star player in college. Now you're mentioned as one of the best defensive backs in the NFL.

You've covered tall receivers, and you've covered fast receivers. You've covered big receivers, and you've covered skilled receivers.

But this week, the Detroit Lions are on the schedule, and you're about to deal with all those traits in one imposing package. You're tasked with defending Calvin Johnson, the 6-foot-5, 236-pound superstar who ran a 4.35-second 40-yard dash in borrowed shoes at the 2007 scouting combine.

"It should be illegal for a guy to be that tall and that big and that fast. They should have banned him from the NFL," Oakland cornerback Charles Woodson said, laughing. "But he's one of those guys, man -- he's a freak of nature."

You've seen the film. You've watched him embarrass defenses and catch touchdown passes in triple coverage. You saw him rack up 329 yards on 14 catches -- the most receiving yards in a regulation game in league history -- when the Dallas Cowboys challenged him with single coverage last season.

Eventually, you will find yourself in a situation where your help disappears, and it's just you against him. At that point, you realize that facing Johnson is like nothing else in football.

"If the safety is not over the top of you and that 6-foot-5 giraffe who is running a 4.3 40 on a [go] route ..." said Cortland Finnegan, who's faced Johnson in college and the NFL. "That's when you go, 'We've got issues. We've got problems.'"

This is your assignment. Here, through the eyes of those who have done it before, is what the experience is like and how to handle it.

'You can't prepare for him'

Heading into training camp, Johnson said he thinks the Lions are capable of winning the Super Bowl. If that is to happen, Johnson will have to be at his best even as opponents devise new plans and tap new personnel to impede him. Detroit's NFC North foes combined to draft seven defensive backs this year -- including two first-rounders.

They will soon learn that preparing to face Johnson is unique. A number of NFL players are difficult to emulate with a scout team -- Minnesota Vikings running back Adrian Peterson and Cincinnati Bengals receiver A.J. Green are two prime examples -- but even among elite players, Johnson poses particular problems.

Calvin Johnson demolished Brandon Carr and Dallas to the tune of 14 catches and 329 yards last season. Gregory Shamus/Getty Images

Johnson has been targeted an average of 9.5 times a game during his career -- more than all but a handful of receivers. His physical attributes, combined with that work rate, demand a different kind of preparation.

"When you go against him, you count on the scout team wideout that mimics him and acts like Calvin Johnson," New York Giants cornerback Dominique Rodgers-Cromartie said. "But you'll never get the real picture."

Johnson's height, speed and bulk make it virtually impossible for defenders to get an accurate read on what they will face come game day. It's not just physical gifts that give Johnson an advantage. He spends a day every week dissecting his routes and locations. He critiques every element of his performance in the previous game and prior matchups.