Manager Ole Gunnar Solskjaer said on Friday that United had asked for Greenwood to be left out of the squad so he could rest following his breakthrough season at Old Trafford.
The Daily Mail says Solskjaer's comments were met with surprise and anger at the FA. Sources say the issue of leaving Greenwood out was discussed as part of the usual dialogue between club and country over a player's welfare, but they saw no problem with having him in the squad.
The teenager was sent home from England duty in shame after he and Phil Foden broke strict coronavirus protocols to invite Icelandic girls back to their hotel after their senior debuts
They also claimed United were informed out of courtesy of the intention to put Greenwood up for interview and no objections were raised at the time — while there is amazement at the FA that Solskjaer does not have Southgate's number.
The England manager is also unhappy over the accusations, particularly after he went out of his way to defend United captain Harry Maguire following his arrest in Mykonos last month.