New manager Louis van Gaal says he will sit down with his squad members on their return from the United States and inform them of their fate.
The 25-man squad will head back to Manchester in the early hours of Tuesday morning, following the International Champions Cup game final against Liverpool in Miami.
Among those reportedly facing uncertain futures are Javier Hernandez, Shinji Kagawa Wilfried Zaha, along with Marouane Fellaini and Anderson who did not make the trip west.
The Dutchman said: "I shall make judgements after the tour. I have let all the players play so I know now more than I did before.
"But in football, you have to judge. Always, you have to give a chance to a player to make a transfer when you see that his perspective is not so high to play.
"You have to say it in advance. When you say it on August 31st, it's too late. I shall say to the players what I think after the tour."
Van Gaal has sent coach Marcel Bout back to England to work with the likes of Robin van Persie, Adnan Januzaj, and Fellaini, who have been given time off following their exploits at the World Cup.
"They (Van Persie, Fellaini and Januzaj) have already trained. I sent Marcel Bout back to train them, along with Nicky Butt," Van Gaal said.
Van Gaal thinks Van Persie is unlikely to be fit to face Swansea on August 16, but the other two could be in contention for United's Premier League opener, depending on how they react to training.
"I have to look at Robin van Persie if he is coming back or not," said Van Gaal, who coached the striker at the World Cup.
"But if you have three weeks holiday and only four days training before the Valencia friendly (on August 12), you are not fit enough.
"For the first game in the Premier League, it's possible but I don't think so."
United's money-spinning tour of the US started amid a blaze of publicity in Los Angeles, but two-and-a-half weeks later, their presence in the US is a lot more low-key.
Only a couple of hundred invited guests turned up at the Sun Life Stadium to watch United's final training session in America.
The session was more of a warm-down as they only played Real Madrid on Saturday night.
On the eve of the match, Liverpool manager Brendan Rodgers said Van Gaal is facing a totally different challenge to any other he has faced in his long and successful career.
Van Gaal, who has won titles in Spain, Holland and Germany, says he is up to the challenge.
"That's why I'm here," he said.
"Maybe he is right because I have to experience that but I was also in Spain and in my first year I won three titles, in Germany I won two titles.
"If I win one here, we will all be happy."
Van Gaal is expected to ring the changes for the final in Miami, which kicks off at 1am BST on Tuesday.
The winner takes home a prize of one million US dollars (£600,000).
Watch Manchester United take on Liverpool live on Sky Sports 1HD from 12.30am on Monday night.