Michigan coach Jim Harbaugh has hired Maurice Linguist and George Helow to be assistants on defense, the latest moves that have reshaped his coaching staff. Harbaugh announced the additions Wednesday night, adding that defensive line coach Shaun Nua has agreed on a contract extension and confirming Brian Jean-Mary will return to coach linebackers. Harbaugh hired Baltimore Ravens linebacker coach Mike Macdonald as defensive coordinator on Sunday, replacing Don Brown, who is now defensive coordinator for the Arizona Wildcats.