The league had asked the high court to dismiss the lawsuit entirely. An appeals court had tossed out a federal challenge to the NFL suspensions, but said a state court could decide related issues.
The NFL cites the National Labor Relations Act, saying its collective bargaining agreement with the players' union protects its drug policy from being challenged in state courts. But the Williams teammates say the league violated state labor laws in applying its drug policy.
The high court's refusal to intervene at this stage is a further setback for the league, which has been trying for more than two years to punish the players.