The CFL canceled its 2020 season Monday, citing what commissioner Randy Ambrosie said would have been "significant financial losses" if the league had played during the coronavirus pandemic.

The league pledged to return in 2021. At the heart of the issue were a series of Canadian government regulations that effectively eliminated the CFL's primary source of revenue -- ticket sales -- and also would have made it a challenge for United States-based players to travel to Canada.

The league developed preliminary plans for a shortened season based in Winnipeg, in a bubble environment. But the Canadian government rejected the CFL's request for a $30 million loan to help fund it.

"Even with additional support," Ambrosie said in a statement, "our owners and community-held teams would have had to endure significant financial losses to play in 2020. Without it, the losses would be so large that they would really hamper our ability to bounce back strongly next year and beyond. The most important thing is the future of our league."

The CFL joins the XFL and two major American college conferences -- the Big 10 and the Pac-12 -- in canceling their 2020 seasons because of the pandemic. The XFL was sold earlier this month in bankruptcy proceedings and could return as early as 2021.

The NFL, whose revenues are based largely on television contracts, has begun its third week of training camp and is on track for an on-time start to its 2020 season next month.