Attorney Peter Ginsberg said Thursday that Williams would appeal the decision.
Williams had sued the NFL to overturn a pending six-game drug suspension. He contended that the league violated protocol in collecting urine samples.
Williams faces a trial on a drunken driving charge in August. He was arrested in Denver on Nov. 12, 2010, when he was spotted driving his car without headlights. He was cited with DUI and taken to a detox facility.