Shohn Huckabee and Carlos Quijas were sentenced to five years in early 2010 after Mexican soldiers said they found about 110 pounds of marijuana in Huckabee's vehicle.
The men say the drugs were not theirs and the Mexican army tortured them.
Huckabee's father, Kevin, told the El Paso (Texas) Times Tuesday the case was transferred to Culiacan, Sinaloa, but the judge there "has done the same as the ones in Juarez -- they have said one thing and done another."
Other inmates in Juarez with similar cases have filed petitions and won release, he said.
"The only difference I can think of is that they are American," Huckabee said.
The father said he may go to the Inter-American Court of Human Rights, but the most likely option is to seek to transfer Shohn Huckabee to a U.S. prison.
Shohn Huckabee has previously rejected the idea because it would mean admitting guilt and incurring a permanent U.S. criminal record.