The Vikings had six players who did not practice on Thursday -- four because of concussions.
That group included Brett Favre, Sidney Rice, Madieu Williams and Erin Henderson. All four must pass a battery of tests before they will be cleared to practice and play.
Cornerback Asher Allen (abdomen) and fullback Naufahu Tahi (ankle) also did not participate.
Safety Tyrell Johnson (knee) was limited. Adrian Peterson (knee) had full participation.
For the Lions, wide receiver Calvin Johnson (ankle), cornerback Chris Houston (shoulder) and linebacker Landon Johnson (concussion) did not practice.
Running back Jahvid Best (toe), defensive end Lawrence Jackson (groin) and quarterback Drew Stanton (left shoulder) were limited.
