Enzo Maresca has informed the senior professional that he is not part of his plans as he seeks to cut down on a bloated squad.
The experienced England international is reportedly assessing his options and Chelsea will not stand in his way if he wants to leave.
In his late 20s, the star can bring experience to a squad while still having years left to operate at the top level.
The player in question is none other than Ben Chilwell, with talkSPORT reporting Chelsea's offer to United.
Both Luke Shaw and Tyrell Malacia are still injured, with left-back having been a problem position for United for long stretches of the past year.
While Diogo Dalot, Noussair Mazraoui, and Lisandro Martinez could step in, it is not their natural position, while 17-year-old Harry Amass is more of a long-term option than a quick fix. Dalot played in the 1-0 win over Fulham on Friday night.
'With Chilly, he's a lovely guy, but I said he is going to struggle with his position. If you find this brutal, it is up to you to decide.
Maresca admitted that Raheem Sterling and Chilwell are part of a group training away from the main squad.
'The situation with both of them is quite clear,' he said.
Diogo Dalot played left-back against Fulham, with Luke Shaw and Tyrell Malacia injured
'They are Chelsea players. But it's not possible to give them all minutes. Those who want minutes, they are better off to leave.
'I try to be honest. I spoke with Raheem before the Manchester City game. I said he will struggle to get minutes with us and this was the reason why he was out.
Chilwell, 27, was informed during the two-week tour of the United States that he is not the proper fit for what Maresca wants from his full backs.
Speaking ahead of facing Servette, who Chelsea must beat over two legs to ensure they are in the Europa Conference League beyond August, Maresca said: ‘Brutal? I don't think so. I just try to be honest.'