Rashford hasn't made the matchday squad for the past three games.
Neville said: "It is not really big team news any more.
“It is something of a norm, a pattern has developed over the last week. It was a surprise last weekend.
"It is getting to the point where you leave him out three games on the bounce something really is obviously going wrong or has gone wrong.
“And it is not looking great for both Marcus' future at the club or Manchester United keeping him either.
"I suspect it is getting to that point in the journey where it has got an inevitable ending.
"It is a distraction for the manager. It does become obvious that he probably has to leave and that the club want him to leave - it will probably work for both parties.”
On Rashford's potential departure next month, Neville also said:"There are good examples as well of players who have struggled at United.
“Jadon Sancho has gone to Chelsea and is doing better, Scott McTominay wasn't struggling but he left to go to Napoli and he is doing well, so Marcus might think it is the right thing for him as well."