It is the IMPACT testing portion that Vick failed.
IMPACT (Immediate Post-Concussion Assessment and Cognitive Testing) is a computerized test that measures things like memory, attention span and reaction time.
The results are compared to his baseline results; the one he took before the concussion. So he is not back to normal yet.
Action News spoke with an expert to find out if this is common more than two weeks after a concussion.
It has been 18 days since Eagles quarterback Michael Vick suffered what team officials called a "significant" concussion.
Since that time he has been resting, undergoing medical tests, and doing post-concussion IMPACT testing.
The computerized assessment is used by most teams in the NFL and also many high schools.
Dr. Sean Grady is the head of neurosurgery at the Hospital of the University of Pennsylvania.
He is not treating Vick, but says failing an IMPACT test more than 2 weeks after a concussion is not unusual for any athlete and especially not for one who has been hurt before.
"Individuals who have a history of concussions have more difficulty getting back to where they were in terms of a baseline performance, and the recovery itself takes longer," says Dr. Grady.
The only treatment we know so far is time and rest.
"Putting the brain at rest the way you would put a fractured limb at rest," said Dr. Grady.
Dr. Grady says typical recovery for a younger athlete is four weeks. It varies for professionals.
But because concussions are now getting more attention, and so is their potential for causing long-term complications, he believes teams are acting more cautiously.
"We do know if you put someone back into play when they are not back to normal that can impair them even further," Dr. Grady said.
Researchers are still studying what those long-term effects are and why they happen.
They say once someone gets one concussion, they are at a greater risk for another if they return to play too soon.
Multiple concussions have also been linked to persistent headaches, depression and thinking problems.
Vick could be tested again as soon as Friday, but for now, he will continue to rest.