We know the Raiders are headed to Las Vegas, the only question is when. Last week, the Las Vegas Stadium Authority board unanimously approved the team's lease at their soon-to-be-built $1.9 billion stadium, and it will open in 2020.

And when the Las Vegas Raiders take the field in that shiny new stadium, fans will be able to legally place bets from their seats.

While the stadium lease includes language prohibiting "gaming or gambling," the stadium authority and Nevada gaming officials say there is nothing in the lease blocking access to popular mobile sports betting apps that are legal in the state of Nevada, according to ESPN.com's David Purdum.

NFL spokesman Brian McCarthy told Purdum in an email that the Raiders "are required to abide by league rules on the matter," though McCarthy didn't offer specifics about what that meant.

NFL commissioner Roger Goodell said this spring that the league likely wouldn't request that the Raiders be removed from betting boards at Nevada sportsbooks, and gaming commission chairman Tony Alamo told Purdum that the league "has not approached me for any policy decisions" regarding the stadium-mobile betting issue. One option could be to disable the mobile sports betting app inside the stadium during games.

The good news is that the NFL has time to figure out what to do; the Raiders still have at least two more seasons in Oakland before relocating to Vegas.