Manchester United's decision to sell Scott McTominay has proven to be a 'bad call'.

That is the view of former United defender Jaap Stam, who insists he would not have sold the 28-year-old in the summer.

The United academy graduate joined Napoli in the summer for around £21million and has made an excellent impact in Italy. He is a crowd favourite at the Diego Armando Maradona Stadium and has been an ever-present in Antonio Conte's side's Serie A title push.

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Having been a favourite under Jose Mourinho, Ole Gunnar Solskjaer and Ralf Rangnick, Erik ten Hag sold him on to help make way for new arrivals in the summer.

But Stam, who won the treble for United as a player in the 1998/99 season, believes that has proven to be a mistake.

"Scott McTominay has been a very important influence at Manchester United even though he wasn’t a guaranteed starter," Stam told SportsLens.

"He scored goals and had a big impact and those are the players you don’t want to lose as a football club.

"Leaving might have been a good step for him, as is currently being discussed with Marcus Rashford, but he may well have wanted to stay.

"He has been a very important player for Napoli and his confidence is growing because he is starting most games and overall I think selling him was a bad call at United.

"Sometimes you have to make tough decisions as a club and I understand that, but I wouldn’t have been keen to sell McTominay."

Ruben Amorim has since replaced Ten Hag in the dugout and introduced his 3-4-3 system that earned him great success during his time in charge of Sporting CP.

However, United have won just four of their nine matches under the Portuguese boss and Stam feels he will need support in the January transfer window to help United adapt to Amorim's vision.

"At the moment it's still not very dominant in how they play within the new system, despite there being a few wins which was similar for Ten Hag during his start at the club," Stam added.

"I think the manager knows that the team isn’t up to standard yet, that’s why there will also be interest in the transfer window and looking at players that might need to be signed and also players who could head in the other direction.

"You need defenders who can play in big spaces, especially when the wing backs are high up the pitch and two midfielders who can be good in possession but also have the legs to get up and down the pitch.

"The forwards need to be able to make runs in behind but also drop into deep positions, that’s why the manager is testing everyone and seeing if they can perform to his standards. We’ve seen some players struggle with the intensity of the Premier League."