Shields, who was injured during last week's win over St. Louis, is still undergoing tests according to head coach Mike McCarthy.
"He's making progress and he'll be seen again tomorrow," the coach said.
Packers defensive end Ryan Pickett is questionable for the Vikings game, also because of a concussion. McCarthy said Pickett suffered the concussion sometime during practice on Thursday.
"Every quarterback has a starting point in his career. We're not looking at him as a rookie, we're really going in there to stop their offense," said McCarthy. "A big part of their offense is there running game."