Cash strapped Sunderland are forced to sell some of their star players after they dropped down to the third tier of English football.
The 23-year-old has been impressive for the Black Cats since he joined them in 2016 from Manchester United. There have been reported interest from the likes of Wolves and Brighton. However, Boro moved in quickly to snap him up.
Sky Sports reported that the Northern international is due to have a medical on Monday ahead of a transfer worth in the region of £5m.
Boro will be looking to secure promotion to the Premier League after coming close last season. And signings like McNair certainly will help in securing that objective.
He is a highly talented midfielder and should be a brilliant signing for Tony Pulis’s side. He is versatile, and would add sufficient depth and quality to the side.