NBA Commissioner Adam Silver says it's time for a new approach to betting on sports.

In an op-ed article for The New York Times published online on Thursday, Silver says fans should have a safe and legal way to gamble on professional games. He suggests a federal framework that allows states to legalize sports betting. He says new regulations would help prevent underage betting while educating those with a gambling problem about how to bet responsibly.

Sports leagues have long opposed gambling on games, claiming it creates incentives for game-fixing. It is currently only legal in Nevada; New Jersey is moving toward legalization — against the opposition of all four major pro sports leagues.

Silver says new laws would have to protect the integrity of the sports.