GOV. CHARLIE BAKER said he plans to file legislation that would authorize the Massachusetts Gaming Commission to oversee the development of betting on professional sports and assess a 12.5 percent tax rate on daily fantasy sports contests.

In a press release, Baker said the commission would be authorized to grant sport wagering licenses to existing casino licensees – MGM in Springfield, Encore in Everett, and Plainridge in Plainville – for on-site and online betting. In addition, “unaffiliated entities” could apply for licenses to offer online wagering.

The press release said the tax rate for on-site sports wagers under the governor’s proposal would be 10 percent and 12.5 percent for online bets. All of the money raised from wagering on professional and fantasy sports would go to support local aid to cities and towns, generating an estimated $35 million in fiscal 2020, which begins July 1.

States have been gravitating to sports betting ever since the US Supreme Court struck down a law that barred states from authorizing betting on professional and college sports. Eight states, including Nevada, Delaware, New Jersey, Mississippi, West Virginia, New Mexico, Pennsylvania, and Rhode Island, already offer sports wagering.

On Beacon Hill, a number of lawmakers have already filed legislation authorizing sports betting. Baker’s proposal is likely to build momentum for the effort.

On Tuesday, at a press briefing to announce his appointment of legal aide Cathy Judd-Stein as the new chairman of the Massachusetts Gaming Commission, Baker gave no indication he was preparing to file sports betting legislation. “When the Supreme Court decision was issued last summer, I think I said we were going to take a good look at our options and, if appropriate, work with our colleagues in the Legislature on that one going forward and that’s still our position,” he said.

In his press release on Thursday, Baker said: “Expanding Massachusetts’ developing gaming industry to include wagering on professional sports is an opportunity for Massachusetts to invest in local aid while remaining competitive with many other states pursuing similar regulations.”