The heads of Atlanta’s big four professional sports teams continued their push for the legalization of online sports gambling in Georgia, promising Thursday that legislation will be introduced soon.

Steve Koonin, president and chief executive officer of the Atlanta Hawks, told a group of more than 100 journalists and business people that he didn’t know which legislator would bring the proposed legislation to the floor or when.

But, Braves chief executive officer Derek Schiller said, it will happen “very soon.” The Falcons and Atlanta United are also backing the idea

Team executives contend that sports gambling is already happening in the state, just illegally. Legalizing it will drag it into the sunlight and allow the state to regulate it, tax it and limit it to online, they told the Atlanta Press Club.

Such gaming will help create more engaged fans, they said, which is critical in an age of declining ratings for traditional sports broadcasts.

But gambling opponents argue that it will exacerbate social problems associated with the industry — such as family income disruption. Gambling would become as easy as sending a text on the smartphone in your pocket, they contend.

A casino is a fixed place that a person has to drive to, which can create a barrier, said Virginia Galloway, a Georgia lobbyist and the regional director of the Faith and Freedom Coalition.

“With a phone, it is like you have a casino in your pocket. It is open 24 hours a day, seven days a week,” she said.

Legislation that would legalize horse racing or casino games is introduced every session, but so far there’s been little support from lawmakers.

Koonin and friends want a bill that will allow gambling on professional sports, not college, and bets could be made on anything from who makes the next 3-pointer to which team will win. Gamblers would have to deposit money in their gaming accounts to bet, so no one would be betting on borrowed money.

They believe it will build a new generation of young fans.

He said the NFL estimates that $1.5 billion is already being gambled illegally in Georgia yearly.

Galloway and other opponents believe the costs, from increased crime to a new generation of gambling addicts, would be too high. She pointed to studies by former Reagan White House economic adviser Earl Grinols, also the author of “Gambling in America: Costs and Benefits,” who estimated that every dollar spent gambling brings $3 in community costs.

“What I am worried about is the young father who is not buying clothes or food for his family because he is addicted to this,” she said.

The bill’s champion would have to step up soon. About a quarter of the General Assembly session has already passed, and any new legislation would have to be introduced before March 12.