In a decision that could drastically reshape the world of college sports, a federal judge ruled on Friday that the N.C.A.A.’s decades-old rules barring payments to college athletes were in violation of antitrust laws.

In a 99-page ruling, Judge Claudia Wilken of United States District Court in Oakland, Calif., delivered a resounding rebuke to the foundation of the N.C.A.A., issuing an injunction against current rules that prohibit athletes from earning money from the use of their names and images in video games and television broadcasts.

The decision in the so-called O’Bannon case would allow universities to offer football players in the top 10 conferences and all Division I men’s basketball players trust funds that can be tapped after graduation, giving players a chance to share in the billions of dollars in television revenue they help generate for their colleges and the N.C.A.A.

The ruling, which would take effect in 2016, does not mandate that players be paid. But it could allow universities to engage in bidding wars for the best athletes, though the N.C.A.A. would probably try to prevent that by capping payments, which Judge Wilken said was permissible.