The Nevada State Athletic Commission will decide the fate of Julio Cesar Chavez Jr. in late February.
The 26-year-old Mexican fighter tested positive for marijuana in September after his first professional loss, to Sergio Gabriel Martinez by unanimous decision.
At a meeting Tuesday, commissioners asked why Chavez had not yet returned to Nevada for disciplinary action.
Attorney Donald Campbell said the former middleweight champion was stuck in Mexico, unable to obtain a visa.
Chavez could receive a lengthy suspension or a significant fine on his $3 million purse.
Chavez (46-1-1) has already been suspended once, for testing positive for a diuretic in 2009.
His promoter, Bob Arum, said in September that he did not see marijuana as a performance-enhancing drug.
