The 39-year-old former England captain, who began his coaching career alongside Eddie Jones with Japan in 2012, is set to join Leicester Tigers following the Rugby World Cup,
according to BBC Radio Leicester.
Their report read: "The exact nature of Borthwick's role with Leicester is not yet clear, nor is the impact his arrival would have on head coach Geordan Murphy."
Tigers,
who were put up for sale in June, are looking for a major improvement on their second-from-bottom finish last season.
Leicester have so far declined to comment.