Los Periquitos succumbed to a 1-0 defeat at the hands of title-chasing Atletico Madrid on Saturday, leaving the Barcelona-based outfit in ninth place, seven points behind Real Sociedad in the final Europa League spot.
However, despite rumours that Madrid are interested in securing his services, Casilla, who left the Santiago Bernabeu in 2007, insists that his only interest is in helping his current club finish as high up the Liga standings as possible.
"Nothing has happened," the 27-year-old told Goal. "I cannot give you an answer. We'll talk when something happens.
Espanyol have enjoyed a solid season so far after finishing 14th in their previous Primera Division campaign, and had won three of their last five before meeting Atleti on Saturday.
"I think in the first half have been better defensively than offensively, but the team was fine," he said of the game at the Vicente Calderon.
"It was quiet, we didn't have much trouble. After conceding the early goal in the second half, we went for the draw. We gave everything, but it wasn't to be.
"Our goal right now is not Europe, it is staying in La Liga. Europe is far away."