The wait-and-see regarding Michigan coach Jim Harbaugh and his future — will he return to coach the Wolverines for an eighth season or return to the NFL — has taken an interesting turn. Harbaugh, 58, is interviewing with the Minnesota Vikings for their head-coaching vacancy, a source confirmed to The Detroit News on Saturday. Pro Football Talk was the first to report the interview. Harbaugh has, according to the source, informed Michigan of the Vikings interview. If Harbaugh were to go to the Vikings, it would mark his return to the NFL. He left the San Francisco 49ers after four seasons to ta…