Wayne Bridge doesn't think that Chelsea are capable of replacing Eden Hazard, with Cristiano Ronaldo and Lionel Messi the only two players who could match his impact for the Blues.
Hazard is one of Madrid's primary targets this summer and he has spoken openly about moving to Los Blancos to play under his idol, Zinedine Zidane.
Christian Pulisic will soon be arriving at Stamford Bridge from Borussia Dortmund in a £58m ($76m) move but Bridge isn't convinced that anyone, apart from Ronaldo and Messi, could replace Hazard.
"If Chelsea lose Hazard, I don't know how they could replace him," Bridge told Goal. "I couldn't think who they would sign because Hazard is one of the best players in the world. I would think only Messi or Ronaldo could replace him. I think if they do lose him, they can't replace him.
"That's why I worry that Chelsea could struggle even more than they are doing at the moment. He has been a huge part of the club's season with goals and assists. I would love to see Hazard stay to help the club compete and he has been so good for the league, but we don't know what will happen."
Maurizio Sarri's side have had a mixed season but their 1-1 draw at Old Trafford has at least ensured they are in prime position to reach next season's Champions League.
The Europa League represents another route to qualify, with the Blues facing a semi-final second leg clash against Eintracht Frankfurt following a 1-1 draw from the first meeting between the two sides.
Bridge, though, is surprised Sarri is still in a job, particularly considering the various controversies that have marred the campaign, including the incident with Kepa Arrizabalaga in the Carabao Cup final.
"I am surprised that the manager is still at Chelsea, to be honest," he added. "Especially after what has happened at Chelsea, you have had the goalkeeper undermining his manager where he should have been dragged off. The fans aren't happy with the style of football.
"You have the issue with Jorginho and [N'Golo] Kante. Are they getting the best out of each other? Kante is good at getting around the pitch, but his final ball isn't suited to playing further forward and fans aren't happy with that. [Callum] Hudson-Odoi and [Ruben] Loftus-Cheek maybe should have played more and sooner.
"You have got a situation where they and Man United seem to be on the slide. The ownership of the club has entered an awkward spell. Something is going to have to change, you would look to transfers but you worry about the ban.
"Could another manager get more out of the players and make them a better unit? Perhaps, but I still would worry that they don't have enough to compete with Liverpool or Man City. You look at those two teams and with the age of their players and they will add to it.
"Pep Guardiola improves players and City keep signing quality players so it is hard to compete. Liverpool are giving it a good go at the moment but the style of City's play is unbelievable.
"I feel Bernardo Silva has been the best player in the league, he is so technically gifted, so comfortable on the ball and a credit to himself. Pep has also improved him a lot."
Now 38, Bridge was forced to retire from football in 2014 due to a knee problem and he says that life after professional football can be tough, advising young players to prepare in advance and think about what they might want to do after hanging up their boots.
"You go from playing football to have nothing to do but pick your kids up and take them to school," Bridge added. "If there is something I would go back and change it would have been to have lined up some other interest outside to go into after football. That's one bit of advice I give to young professional footballers, to set that up.
"Luckily, I have been able to go on to do TV stuff. I am into coaching and punditry, but I do miss being able to run around and kick a football which I can't do because of my knee. I had always been alright but it plagued my last season at Reading.
"There were a lot of problems in the whole of the last season, I had a load of operations that they thought would fix it. I had a problem with my cartilage. I thought I could play again but I just couldn't. I wore all my cartilage away so I ended up just having bone-on-bone.
"So there was no chance of getting back and playing football. Retirement was something that was forced upon me rather than something I chose to do. I think if I had an option to be still playing, I think like most people I would. Even now in everyday life, it effects me.
"When I am playing with the kids in a kickabout, I come away sore for a couple of weeks. I can run in straight lines but with football and the change of direction, impact on the joints and the stop-start, it just causes too much pain, and I don't have much movement in it."
Wayne Bridge was speaking at the London leg of The Official Coca-Cola Premier League Trophy Tour. Find out more about the tour at https://www.coca-cola.co.uk/trophy-tour #TheOfficialTrophyTour