The Federal Bureau of Prisons' website lists Nassar as an inmate at Oklahoma City's Federal Transfer Center. That facility is typically used as a stopover for inmates who are being placed in a new location.
Nassar's court-appointed attorneys said in a court filing last month that he was assaulted almost immediately after being put into the general population at the Tucson Federal Correctional Complex.
It is not clear when Nassar was transferred to Oklahoma. The move was first reported by the Detroit News on Sunday.
Nassar pleaded guilty to child pornography charges in federal court last summer. He was sentenced to 60 years for those crimes in December. Nassar, 55, was sentenced to up to 175 years in state prison in January for first-degree criminal sexual conduct crimes.
He appealed the state sentence in Ingham County, Michigan, court last month and asked for a new judge to deliver a new sentence. His appeal was denied. Parts of that appeal, filed by new court-appointed attorneys, claimed that Judge Rosemarie Aquilina was biased and unfair when she sentenced Nassar, who admitted to using his authority as a doctor to sexually assault young female patients. More than 300 former patients have said they were abused by Nassar during the time he worked for Michigan State and served as the national medical coordinator for USA Gymnastics.