The Blancos youth product joined Bayer Leverkusen last year but remains keen on a Bernabeu return and sees his former side as favourites over Dortmund in the Champions League
The 21-year-old learned his trade at the Spanish giants' youth academy but, despite racking up a number of appearances for the B team, he decided to move to the Bundesliga last summer after failing to break into Jose Mourinho's squad.
Carvajal has been nominated for best right-back in the Bundesliga this season thanks to his impressive performances this season and, though he says he is enjoying German football, a Santiago Bernabeu return remains his dream.
"Yes, I would like to return one day [to Real Madrid]. They have an option to buy me back me, too," he told Marca.
"I am trying to work the best I can here, to improve day-by-day and if one day they decide to exercise the option to bring me back then I would accept it straight away."
The Blancos face German giants Borussia Dortmund next Wednesday night at Signal Iduna Park and Carvajal believes that Cristiano Ronaldo will help his former side reach the Champions League final over the two legs.
"When Dortmund are forced to chase after the ball for a long time, they suffer," he told Marca. "In the Bernabeu they could start the game set up to play on the counterattack but without the ball they suffer.
"The other point of difference is that they do not have a player like Cristiano Ronaldo. He could be very important in determining the winner of this tie.
"Borussia do not have a player like him. Madrid have Cristiano, Barca have Lionel Messi and Bayern Munich have Franck Ribery but Borussia do not have anyone who can be as decisive. So Madrid will enter the tie as slight favourites."
Carvajal has made 31 appearances for Leverkusen this season since his transfer from the Spanish capital club in the summer of 2012.