Manchester United will not sanction a full exit after paying big to get Paul Pogba back.
David Moyes is looking to add to his Black Cats squad this summer after replacing Sam Allardyce as manager at the Stadium of Light.
It is thought he is determined to add players that can turn them into a stable Premier League side rather than the team that has continuously battled relegation over the years.
Januzaj is one player they have been linked with after it became apparent the Belgian may not have a role to play under Jose Mourinho.
According to the Daily Mail, Moyes had proposed a permanent switch but United are instead insisting on a loan deal as they would like to keep him on their books for another season at least.
The newspaper reports that they are keen to avoid another situation such as the one with Paul Pogba.
The midfielder returned in a world record move from Juventus this summer after leaving United for just £800,000 four years ago.
While Januzaj has disappointed in recent years, United still feel he is too good to let go just yet, meaning they will only sanction a loan deal this summer.