SAN ANTONIO -- An ex-financial adviser to retired San Antonio Spurs player Tim Duncan has been sentenced to four years in federal prison for defrauding the former NBA star of millions of dollars.

Federal prosecutors say 49-year-old Charles Banks of Atlanta was sentenced during a court hearing Wednesday in San Antonio.

A judge also ordered Banks to pay $7.5 million in restitution.

Banks had pleaded guilty in April to one count of wire fraud.

Investigators say Banks manipulated Duncan -- who retired last year after five NBA championships with the Spurs -- into guaranteeing payment of a $6 million debt related to a merchandising business.

Prosecutors say Banks failed to disclose commissions and loans he received in the deal.

Banks is set to report to federal prison as early as Aug. 28.