According to twincities.com McCauley's injury appears to be nothing serious with McCauley saying

"Just playing football, man," he said. "Weird things happen. I'll be fine."

McCauley injured his right knee while trying to hold up an outside gunner on the second punt of the opening drill and was taken off the field on a cart. "McCauley said he still had tests to undergo, but he was walking without difficulty and with no wrap on the knee"

This is great news for the Vikings and their defense and keeps them relatively injury free heading into pre season (knock on wood)

Can't wait till Green bay!!!