This has been the year of LeBron James, who earned the NBA championship, the Olympic gold medal and Sports Illustrated‘s Sportsman of the Year. And as his outstanding 2012 ends, one persistent rumor has taken hold.

A lot of people believe that James will be returning to Cleveland.

“It’s the worst-kept secret in the league,” one general manager said.

There are reasons to believe it, starting with Miami’s untenable position as a luxury-tax payer. After next season, the Heat will be among the first teams faced with the new “repeater” penalty that threatens them with close to $50 million in luxury taxes, in addition to their expensive payroll.