Alejandro Garnacho, Jadon Sancho, Antony and Tyrell Malacia have been left out of the squad that is traveling to the United States for the pre-season tour, as the four players are seeking transfers away from Old Trafford.
However, despite having to train separately from the first team since United returned for pre-season training, Amorim acknowledged that he would be open to accepting the players back into his squad if they remain unsold.
"Some players need to find new opportunities to create more space in the team, while others clearly desire a new challenge and wish to join different teams," Amorim told reporters in Chicago ahead of Saturday's pre-season match against West Ham United.
"We are simply allowing these players time to reflect and decide. If we reach a point where they need to rejoin the team, they will, because they are our players.
"I am prepared to welcome the players back. They face more competition; if they wish to play in the World Cup next year, they need to be active.
"So I am genuinely pleased with this because it gives me more options. If they must compete against each other for playing time, that is ideal for me."
United have acquired Matheus Cunha and Bryan Mbeumo thus far in the transfer window, while England winger Marcus Rashford has departed to join Barcelona on loan as Amorim's team seeks to recover from a disappointing 15th place finish in last season's league standings.
The club's financial circumstances necessitate that United sell players if they wish to strengthen their squad. Chief Executive Omar Berrada and director of football Jason Wilcox are tasked with identifying buyers for their "bomb squad."
"I know for certain that these individuals - Jason, Omar, and the club - have a target price for these players," Amorim stated. "If that target is not met, they will remain Manchester United players, without a doubt.
"I understand that the interested clubs are waiting until the last minute, but they may face surprises."