Michael Vick has taken another hit, and this one could cost him nearly $20 million. Already facing prison time, the disgraced quarterback lost the first round in his financial battle with the Atlanta Falcons when an arbitrator ruled Tuesday that Vick should repay much of the bonus money he got while secretly bankrolling a gruesome dogfighting ring. The case is far from over. The players' union said it will appeal the ruling by Stephen B. Burbank, a University of Pennsylvania law professor and special master who oversaw last week's arbitration hearing in Philadelphia. The Falcons argued that Vick, who pleaded guilty to federal charges for his role in the long-running operation, knew he was in violation of the contract when he signed a 10-year, $130 million deal in December 2004.