In the wake of allegations posted by a woman on social media, Greenwood was initially arrested by Greater Manchester Police on suspicion of rape and assault.
The 20-year-old was then further arrested on suspicion of sexual assault and threats to kill before being released on bail, and Man United have stated that he will not play for the club until further notice.
A number of Red Devils players appeared to unfollow Greenwood on social media following his arrest, and The Sun reports that this has led to division in the dressing room.
The report adds that some players do not want to pass judgement until the investigation has finished, with Greenwood yet to be officially charged with any crime.
"One player in particular is furious about it. He feels that ditching Mason shows they are not together. If Mason is convicted of what he has been accused of, then clearly all the players will be horrified," a source told the publication.
"But the police haven't even decided if they have enough evidence to charge him or not yet. Some of those closest to him feel the course of justice should be allowed to run.
"But when some of the players started dumping him, they felt they had to as well. One of the players said it showed how the squad wasn't together and showed that too many times they act as individuals."