#2. David De Gea
While this may not be David De Gea's best season in goal, let's not forget that David De Gea is the only Manchester United player to have ever won the Sir Matt Busby Player of the Year Award four times (2014, 2015, 2016 & 2018).
According to multiple news sources, De Gea is holding out on signing a new contract as he believes that he deserves to be paid on par with highest club earners such as Alexis Sanchez who earns £500,000-a-week.
Naturally, should De Gea chose not to sign a new contract, it will mean that United would have to sell him this year lest losing him for free next year. PSG & Real Madrid are two clubs who seem to be interested in signing the Spanish goalkeeper.
Honestly, losing De Gea would be like losing the backbone of the team.