Staal's injury was originally diagnosed as a neck issue, although he was described as having concussion-like symptoms.
Now that the concussion is confirmed, the Rangers will keep Staal out of the lineup until his condition improves.
"Marc has been diagnosed with a concussion," Vigneault said. "He's being watched by our doctors. They don't feel it's as serious as what he might have had in the past. He's feeling better and we'll take it day by day."
Considering Staal's injury history, he isn't likely to be rushed back into the lineup. He missed 35 games in 2011-12 with a concussion and 27 regular-season games last season following an eye injury caused by a deflected puck.
Vigneault said the Rangers were in touch with concussion specialist Dr. Jeffrey Kutcher, who met with forward Rick Nash earlier this season while he recovered from a concussion. Staal and the team concluded that meeting with the University of Michigan neurologist was not necessary at this time.
In 30 games this season, Staal has a goal and two assists.