Adan denied he is now manager Mourinho's first choice for the rest of the season after Spain international Casillas reportedly fell out with the Portuguese.
Adan told realmadrid.com: "I'll train and I will wait for the boss' team sheet, that is who has the power to say who plays.
"I have no idea whether I will play or not and all I have to do is work hard over the coming days and wait for the line-up to be decided.
"If the coach has already decided that I am going to play, then only you know. For me, playing at all is the important thing. Last year I played five or six matches. This year we are in January and I've already passed that barrier.
"Anything that means getting more pitch time is important".
Adan also denied a rift with Casillas.
"Our relationship is very good. I have already said that apart from being teammates, we're friends. He has been great with me," he said.
"Casillas is the captain of Real Madrid and Spain. He brings together all the values of a footballer and a team-mate and has helped me at all times and given me his support and trust".