Former Chelsea midfielder Michael Ballack has warned Eden Hazard that he might be making a huge mistake if tries to engineer a move to Real Madrid this summer.
Ex-Germany international Ballack, who rejected the advances of Madrid when he signed for Bayern Munich from Bayer Leverkusen in 2002, believes Hazard will be "giving up a lot" if he swaps Stamford Bridge for the Santiago Bernabeu.
Madrid have been strongly linked with the Belgium captain but Ballack suspects he will face a challenge to establish himself if he makes the move to the Spanish capital.
"Hazard has a decision to make and he needs to consider what he would be walking away from at Chelsea if he moves to Real Madrid now," Ballack, now a pundit for BT Sport, told ESPN FC.
"Right now, Hazard is the top player at one of the biggest clubs in Europe, living in a fantastic city. Does he want to give all that up and then try to be a success at Real Madrid?
"He should realise that he can be the top player for another few years at Chelsea. It has taken time for him to establish himself at this level at Chelsea and he will need to start again if he moves to Real Madrid.
"I can't give him advice on this. It is not just about a lot of money, even though that does count in a decision for every player. If we just speak about football, he has signed for Chelsea for a long time and he will not have the standing he has now at any other top club. This should be important for him."
Ballack said he could not explain how Hazard's form has been transformed from his disappointing performances last season to his impressive displays during Chelsea's title challenge this term, but suspects reported disagreements with former manager Jose Mourinho may not have been the only reason for his dip in form.
"There must have been a reason why he was playing like he was last season," Ballack said. "He seemed to be that a player like Hazard was unhappy on the pitch.
"Only he can explain the reasons, whether it was the other players or what seemed like his coach. Maybe he had some private problems, we never know.
"This season it is completely a different player. Suddenly, he loves football again, he has freedom. It is difficult for the rest of us to know why. He played in a position that suits him, he had the same players around him as this season, but the performances were so different.
"Sometimes players are sensitive these days. If they feel misunderstood or if they are not getting what they want, they have the power to play below their best. Players have a power now and managers don't always have enough to control them, this is true.
"All we can say so far is that he is fantastic this season and it seems to be working for him again."
Ballack said Chelsea will need to retain the services of Hazard if they are to make a mark in the Champions League next season, though he expects them to struggle to replicate this term's dominance when they return to Europe's top club competition.
"Clearly they need to keep players like Hazard, Diego Costa and the manager Antonio Conte, but it is too early to say how competitive this Chelsea team could be in the Champions League," Ballack said.
"They are still trying to close the gap to the big teams. I don't see that they are in a position to win the Champions League next season. It's surprising that they are dominating the Premier League so much, but the amount of games they will have next season will challenge them.
"This season, we have big spaces between matches and that has helped them with their recovery. We have to wait to see what happens with the coach and the players that come in during the summer and only then we can make judgments on where they would rank against the best teams in Europe."