Hayward played all of the cornerback spots while excelling at Vanderbilt, collecting seven interceptions last year as a senior and 15 overall in college - a school record. Still, playing where he is now for Green Bay has been an adjustment.
"In the slot there is so much space, you have to be familiar with formation, variation and concept," Packers receiver Greg Jennings said. "So you have the guy lining up in front of you, you've got the space, you have to look at what he can potentially do. You have to play that area. You can't just play that guy.
"Casey is doing a great job. His ball skills are outstanding. It is impressive to watch him play. I was watching him on the sideline last week and I was talking to Charles saying, 'This kid is going to be good.' I mean, he's instinctive. You have to be instinctive at that position - and a little savvy as well.
"But he studies, he's smart, he understands concepts."
Hayward can't just match up with a receiver man to man like an outside cornerback. He has to read a formation and imagine how the offense might attack his area. He also could be looking at more than one receiver as potential targets for the ball. Playing slot corner means there are all kinds of route combinations a receiver can run, there's more open field to cover, there can be motion to interpret and there can be stack formations that try to create picks on the slot corner.
That's why Hayward, when asked what his No. 1 job requirement was, said simply: film study.
"There, I am making sure I am in the right spot," he said. "I have to make sure I brought the right coverage."
House said another key point to playing the slot is knowing where the help is - from a safety or even a linebacker.
"He's also a natural knee-bender," House said. "Me, I'm not a natural knee-bender, as you can see . . . "
Hayward also is good at running and moving laterally.