McCready, 31, was arrested last week in Fort Myers, Fla., her hometown, on misdemeanor charges that she scratched her mother on the face during a scuffle and resisted sheriff's deputies.
Deputy District Attorney General Derek Smith told The Tennessean that she violated probation in three ways: by being charged in a new offense; not reporting those charges immediately to her probation officer; and by the nature of the new assault charges.
An official at the Williamson County sheriff's office just south of Nashville said McCready was being booked Wednesday night.
McCready's previous attorney, Lee Dryer, did not immediately return calls to his office on Wednesday after business hours, though information from the Williamson County Court Clerk showed Dryer had withdrawn as her lawyer. It was not yet known if she had a new attorney.
She was on probation for obtaining the painkiller OxyContin fraudulently at a pharmacy in 2004. Still pending was another probation violation charge resulting from a drunken driving arrest in May 2005.
McCready had a hit in 1996 with "Guys Do It All the Time," but has struggled in recent years amid personal problems. Her album "Ten Thousand Angels" sold 2 million copies that year.
The singer was found not guilty of the DUI charge in July 2006 but guilty of driving on a suspended license. She then pleaded guilty to violating her probation but has petitioned to withdraw that plea.