EDEN PRAIRIE, Minn. -- Now that the Minnesota Vikings are in their first week of organized team activities, able to put a full squad on the field for 11-on-11 work, their offense can begin its heavy work learning offensive coordinator Norv Turner's scheme.

The concepts of that offense represent a fairly significant departure from what the Vikings have run in the past. Whether their offensive coordinator was Bill Musgrave or Darrell Bevell, the Vikings' offensive players have worked in West Coast offense-based systems, which identify passing routes by name. Turner's offense has always used the route numbering system developed by Don Coryell -- who developed the scheme -- and asks players to turn route numbers into easily-identifiable concepts.

"This is the first time I’ve been I’m in a numbers system," quarterback Matt Cassel said. "The first thing I did when I got the playbook, I was trying to figure out what exactly does this number mean. Like every offseason -- I think I’ve had seven coordinators in six years -- so it’s a lot of work in terms of flash cards, writing stuff down and memorization. Once you start to conceptualize it, it becomes easier for you.

"For us as quarterbacks, you just can’t see the numbers, whether it’s a 6 is an in-cut. You have to be able to conceptualize that Seam 678 means something and be able to see that whole picture in your mind."

During the team's voluntary mini-camp last month, running back Adrian Peterson likened the Vikings' early practices in Turner's offense to performing "open heart surgery without a license." Peterson's role will change under Turner, as he trades some carries for receptions, but the 2012 NFL MVP sounded more excited about his role as he begins to get a better feel for things.

"Just as a whole what coach Turner brings is pretty amazing and more free. (We're) able to digest everything as a group, and I think it’s going to be fun,” Peterson said. "Where I’m at now, the terminology, I’m starting to pick it up even more. It’s all about staying in that playbook, understanding the terminology and breaking the play down. It’s going well.”