Casillas is expected to be out for a minimum of six weeks meaning he will miss the upcoming Copa del Rey semi-finals against Barcelona and at least the first leg of the Champions League Last 16 clash with Manchester United.
Madrid have been linked with several goalkeepers in the last couple of days, including Queen Park Rangers keeper Júlio César, but the Spanish side decided to target someone who began his career at the Bernabeu.
The 31-year-old Lopez will now battle Antonio Adán for the starting spot.
Real’s initial plan was to sign López on loan. However, a permanent transfer was arranged with Sevilla receiving €3.5 million for the goalkeeper.