Lopez was under pressure going into Real's win over Real Valladolid over his form.
"He's been singled out by a certain section of people. But what mistakes did Diego López make in these two games? He could have possibly done more for one of the goals, but if Casillas had played, we might not have won the two games either. It's very easy to blame the weakest link," Buyo told Marca.
"If Ancelotti decides to start with Diego López, that's because he believes in his ability and because he is in good form. He has said that Diego López will play against Rayo and I think he has shown his authority and that he believes in the keeper."