Frank, formerly coach of the New Jersey Nets, is the second candidate to be formally interviewed for the position, sources said, joining former Atlanta Hawks coach Mike Woodson.
The Detroit News and Detroit Free Press reported in Thursday's editions that the Pistons also have scheduled an interview with Milwaukee Bucks assistant Kelvin Sampson by week's end.
The Pistons have likewise requested permission from the Dallas Mavericks to interview assistant coach Dwane Casey, who was taking part Thursday in the Mavericks' championship parade in Dallas.
Casey and Frank are the two finalists for the Toronto Raptors' coaching vacancy. Both were also finalists in Houston and Golden State for jobs that went to Kevin McHale and Mark Jackson, respectively.