Sportsbooks around the United States have halted betting on college football, as bookmakers try to determine the best approach to a season in flux.

On Tuesday, the Big Ten and Pac-12 announced they were postponing their seasons due to safety concerns regarding the coronavirus pandemic and are looking at the possibility of playing in the spring. The Mountain West and MAC also have ruled out playing this fall, while the ACC, Big 12, SEC, American and Conference USA are aiming to kick off their seasons in the coming months.

Clemson was the consensus favorite to win the national championship, followed closely by Ohio State and Alabama, before sportsbooks halted betting following Tuesday's announcements. Ohio State quarterback Justin Fields and Clemson quarterback Trevor Lawrence were the favorites to win the Heisman Trophy, before betting was stopped on the award.

Caesars Sportsbook's house rules stipulate that bets on the national championship are valid as long as a winner is declared in 2021, meaning that wagers already placed on Big Ten teams like Ohio State, for example, are still live. Bets on the Heisman Trophy winner will be honored as long as the award is presented before March 31 at Caesars.

"When weird stuff happens, like all of this, you can't plan for it," Jeff Davis, director of trading for Caesars Sportsbook, said. "Some of this is going to be handled on a case-by-case situation."

Other sportsbooks were planning to refund bets on teams from conferences that won't play in the fall, and other bookmakers were taking a wait-and-see approach.

"We would refund the teams that don't play," Jeff Stoneback, director of trading for BetMGM in Nevada, told ESPN. "If you've got teams that are in there now and they play the season and a champion is declared, we'd pay off on that. If you've got LSU and they're declared the winner, you'd get paid. If you have USC, we'll give you a refund."

Some sportsbooks' odds specify that the national champion is the winner of the "College Football Playoff championship game," which could cause issues if a playoff isn't possible. Caesars, however, just requires a national champion to be declared.

"If Drake plays Northern Iowa in what the NCAA says is the national championship game, then everyone's on the hook," Davis said.

Most nonconference games have been scratched, but despite the schedule changes, season-win total bets already placed will still be honored at Caesars Sportsbook, as long as the teams play 12 games. The same goes for bets on conference champions, as long as they're determined by March 1.

FanDuel has an "act of God" stipulation in its house rules that includes pandemics and allows the book to exercise its discretion in such situations. FanDuel, like several sportsbooks, was reviewing all options before making any decisions on how to grade any college football bets already placed. But right now there are more questions than answers.

"That's a mess," Stoneback of BetMGM said.