The defender will become the club's first signing of the summer as Mourinho aims to turn United into Premier League champions next season.
With 22-year-old is now on global duty with Sweden for their games against France (a 2-1 win on Friday) and Norway (Tuesday), the earliest any medical can be completed is Wednesday - but the process looks more or less like a formality after United's statement.
Benfica defender Victor Lindelof is to undergo a medical with Manchester United prior to completing a deal worth around £31m, the Red Devils announce.
The Victor Lindelof to Manchester United narrative continues to gather momentum amongst the tabloids.
He was soon linked to some of Eur0pe's biggest clubs and the chase intensified when Sweden captain Zlatan Ibrahimovic, who spent last season at Old Trafford, gave his seal of approval.
Jose Mourinho is reportedly a long-term admirer of the Swedish worldwide, who played all 90 minutes in Friday's surprise 2-1 win over France in 2018 World Cup qualification.
In terms of outgoings, captain Wayne Rooney has to decide whether to fight for his place or move on to pastures new. Real Madrid are no longer said to be in pursuit of United goalkeeper David De Gea, but other players around the club are the subject of speculation and interest.