Singletary told ESPN 1000 in Chicago during an interview Tuesday that he will be the linebackers coach and assistant head coach under Frazier, whom the Vikings made their head coach two weeks ago. Singletary's agent, Bob LaMonte, confirmed in an e-mail to The Associated Press that his client is coming to Minnesota.
Singletary was 18-22 in two-plus seasons in charge of the 49ers, who fired him last month before their final game.
Frazier and the Vikings aren't commenting about their coaching-staff assembly process until it's finalized. Frazier, who is expected to promote linebackers coach Fred Pagac to replace him as defensive coordinator, has several spots to fill on the offensive side.
"You know what, I'll put it this way: a personal failure," Singletary said after his last game with the 49ers. "I'm the head coach of this team, and obviously wanted us to do better, felt that we could do better."
The Associated Press contributed to this report.