Martial is understood to be frustrated with his lack of first-team football under Mourinho, and last month his agent confirmed that the 22-year-old wants to leave Old Trafford, having missed out on France's victorious World Cup squad.
Martial played the full 90 minutes of United's goalless draw with San Jose Earthquakes last night, but after the game Mourinho suggested that the attacker may have to come to terms with the fact that he will be staying at the club for the upcoming season.
"I would like to be in Los Angeles now and I am in San Jose. You cannot do whatever you want in life. I would love to arrive in Los Angeles, to train in Los Angeles and play all my five matches in Los Angeles, and then don't travel, don't change hotel and then go back to Manchester," Mourinho told reporters.
"I would like to play against Leicester on Sunday but I have to play on Friday, so you don't get always in life what you want.
"For me is a very strange pre-season. Pre-season, you try to be motivated and motivate the people around you but is not easy. I did some pre-season with some players but to have 10 players away is very strange.
"So the motivation is to try to train the best we can, to give the players minutes, to give young players an opportunity to develop and that's it."