Manchester City are considering a move for Eze, while Liverpool want Doucoure. But Palace are reluctant to lose either player and will fight to keep them at Selhurst Park.
Palace were boosted last week when they tied down Michael Olise after seeing off interest in the winger from Chelsea.
Roy Hodgson called the contract “best possible news”, but Palace still have an anxious week ahead of them as they try to keep hold of Eze and Doucoure.
Palace hope their £70m valuations of both players will be enough to fend off interest from City and Liverpool.
City plan to make one major midfield signing in the next week after Kevin De Bruyne suffered a serious injury and they lost Ilkay Gundogan to Barcelona.
Liverpool, meanwhile, want to strengthen in midfield after losing Jordan Henderson, Fabinho, Alex Oxlade-Chamberlain, Naby Keita, James Milner and Arthur Melo this summer.