Manchester United have a lot of work to do if they want to strengthen their squad in the January transfer window.

Ruben Amorim will be left wondering what to do next after United lost 2-0 to Newcastle United on Monday night in their final match of the calendar year. The defeat at the hands of the Magpies was also United's last fixture before the January transfer window opens later this week.

With the transfer window opening, rumours have been doing the rounds about the potential business that United may conduct. However, there is a harsh reality facing Amorim in his first winter window at Old Trafford.

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The Manchester Evening News have reported that united do not currently have any money to be able to strengthen their squad with new signings in January. Club sources have insisted that, in order for players to arrive on permanent deals in the New Year, existing members of the squad would need to be sold to raise funds in order to comply with Financial Fair Play and the Profit & Sustainability Rules in the Premier League.

Amorim was asked about the possibility of United making new signings after the defeat to Newcastle. However, the 39-year-old stated that he is not expecting players to be added to his squad in the New Year.

"We don’t have that possibility in January," said Amorim. "You know the situation better than I [do].

"It’s not the case I am not arriving here and I can spend a lot of money, changing all the team. You know the situation so it’s not a point to talk about it."

If United have to sell-to-buy this January, there may be some options in the squad that the Old Trafford hierarchy may be considering. One such player is Marcus Rashford, who has not played in the last five matches for United.

After publicly declaring his desire for a "new challenge" in an interview with Henry Winter earlier this month, Rashford has been heavily linked with a move away from United. It remains to be seen what the future will hold for the United academy graduate, but if the club were offered a transfer fee in January they would be wise to give it serious consideration.

Three other players who could be options for United to sell are Harry Maguire, Victor Lindelof and Christian Eriksen. All three of their deals are set to expire at the end of the season, meaning they could all leave for free in just six months time.

Maguire has the option of a further year in his contract, but it remains to be seen if that will be activated. If offers come in for either Maguire, Lindelof or Eriksen in January, that could help contribute towards boosting the transfer funds available to United.

United would benefit from signing a new left-back or left wing-back in January, too. Diogo Dalot currently plays in that position in Amorim's system, but has not shown the same form he showed during the Erik ten Hag era.

Amorim may want to have a recognised left wing-back in his squad that suits his 3-4-3 system more than Dalot. If that is to be the case, and a replacement can be identified, United may want to consider raising funds via a Dalot transfer.

Antony and Casemiro have also found themselves continuing not to be a regular starters for United since Amorim took charge. Casemiro did start in the defeat to Newcastle, though, while Antony made an appearance from the bench.

Casemiro has 18 months left on his contract plus the option of a further year, while Antony's deal expires in 2027. With enough time still on their contracts, if United were to receive offers for either of the duo, then it may give United some funds to work with in a season-defining January transfer window.