In that article it says this too;
On July 27, NFL commissioner Roger Goodell detailed the conditions of Vick's reinstatement in a letter.
He wrote that the former Atlanta Falcons player, who was incarcerated for 18 months on a dogfighting conviction, was "required to abide by the terms of the supervised release that were imposed on you by the court, which include not committing any further crime, limits on who you may associate with, prohibitions regarding drug and alcohol use, possession of a firearm or other dangerous weapon, and forbidding you to own, possess, or be involved with the sale of any dog."
Looks to me like he violated both the court order and the NFL's rules for his reinstatement unless his supervised release time is up.