Cech said he'd welcome Rooney's arrival at Stamford Bridge.
"I could see him in a Chelsea shirt, as players change shirts," Cech told Sky Sports News.
"He has had a fantastic career with Manchester United but sometimes players need new challenges.
"If that happens, he is a fantastic player and would be welcomed to our squad. At the moment we are in the moment of speculation so we will see what happens.
"He is a great player and you always want to see great players in your team.
"He has his ideas and what he wants. Now the window opens and we will see what the movement is."