If the Rockies make the playoffs in 2020, it’s possible Coloradans could legally bet on the innings from Coors Field.

Two lawmakers introduced a bill Thursday that would ask voters in November whether they want to legalize sports betting throughout the state and tax the new industry’s net proceeds at a rate of 10 percent starting in May 2020.

“My goal has always been to eliminate the black market,” House Majority Leader Alec Garnett, D-Denver, said.

His bill with House Minority Leader Patrick Neville, R-Castle Rock, would allow the 17 companies that own Colorado’s 33 casinos to apply for something called a master license. The license would give them permission to open a physical sports book at one of their casinos and to contract with a company of their choosing to operate an online sports book or cell phone app.

One important thing the bill doesn’t do is let racetracks apply for master licenses.

“I wanted to maintain the intent of voters to keep gaming in those three mountain towns,” Garnett said.

In 2014, voters overwhelmingly rejected a proposed state constitutional amendment to expand gambling to certain racetracks around the state. The campaign, which was heavily funded by the casinos, was one of the most expensive in Colorado’s history.

Garnett has “done a good job of bringing together all the stakeholder groups,” said Peggi O’Keefe, a lobbyist for Colorado’s casinos who worked with him on the legislation.

O’Keefe told The Denver Post that Colorado’s casinos support the bill.

It puts sports betting under the regulatory thumb of the Division of Gaming and gives the agency discretion to make rules about things like how to verify a person’s age before letting them bet through an online system.

O’Keefe previously suggested Colorado follow Nevada’s example and verify players in person at a casino before opening an account. The challenge with that method of verification is that Colorado’s casinos are clustered in one location, which means players in the four corners of the state would spend a day traveling to and from the mountains to open an account.

Other states that allow sports betting, like New Jersey, let players register through an online verification system.

New Jersey is actually the reason sports betting is even an option for Colorado. The state successfully challenged a federal law called the Professional and Amateur Sports Protection Act that limited betting on sports to a handful of states. The U.S. Supreme Court struck PAPSA down as unconstitutional in May 2018.

Nearly 30 states started working on legalizing sports betting following the ruling, and Colorado’s proposal mirrors a lot of what’s happening in places like Delaware and West Virginia.

Colorado’s ballot question would ask voters if the state could collect 10 percent of the net sports betting proceeds. That’s about what New Jersey and Delaware currently charge their casinos. Nevada, which levies a 6.75 percent tax on gross revenue from sports betting, is the lowest.

“It’s not a huge margin on sports betting,” O’Keefe said. “This is a number we can live with and still make a profit.”

How much of a profit the state will make off sports betting isn’t clear yet, but she estimated Colorado would take in about $7 million to $9 million annually.

“Nevada made $15 million when they had a monopoly,” she said.

Candidates during the 2018 election threw out estimates 10 times as high, but once the experts started crunching the numbers they quickly realized Colorado would never collect enough money from bets on the Broncos — even if they make it to the Super Bowl — to pay for Colorado’s transportation project backlog or even fully fund all-day kindergarten.

Garnett and Neville plan to put the sports betting revenue toward Colorado’s water plan if voters say yes in November.