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 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.