The Chilean star will soon be able to join up with his team in America.
He has already missed the first match of the trip against Club America in Arizona, but will still be key for the coming matches and in training.
Mourinho has been worried about preparations for the coming season, with his World Cup players still not returned, and Sanchez not being able to travel.
Sanchez has been training at the Aon Training Complex for the last few days, but has his last session there on Thursday.
He is due to fly out and meet the rest of the squad as soon as possible, now that his visa has been sorted.