Diego Costa is worried that Chelsea team-mates Eden Hazard and Thibaut Courtois could both be tempted to leave for Real Madrid.
Courtois has regularly been linked with the European champions this season due largely to a drop in form of Madrid goalkeeper Keylor Navas.
Hazard, meanwhile, is reportedly Madrid's prime target ahead of next season, with the Belgium international having described head coach Zinedine Zidane as his footballing idol while he was growing up.
And Costa believes neither player would find it easy to reject the advances of the LaLiga leaders.
"If Real Madrid were to sign Hazard and Courtois... well, poor Chelsea!" the Spain striker told Cadena COPE.
"Hazard is happy here but everyone knows that, when teams like that knock on your door, you have to think about it.
"He is very calm, he is very much loved here. He is a top player and I would be happy if he stays."
Asked about Courtois, who spent a successful three seasons on loan with Atletico Madrid, Costa said: "Real Madrid want the best goalkeepers and Courtois is one of them. He has a contract here and it would be a shame if he left.
"Thibaut loves Spain, his family lives there. He is happy here but you never know."