
Jackson Martinez joined Atlético from Porto for $35.3 million in July 2015, but the two main Madrid clubs face a transfer embargo until July 2017.

Croatia midfielder Mateo Kovacic (left) joined Real Madrid from Italian side Inter Milan for $29.2 million in August 2015.

Argentine striker Luciano Vietto made the switch to the capital from Villarreal, costing Atletico $18.7 million in June 2015.

Real Madrid signed Brazilian right-back Danilo from Porto for $31.7 million in July 2015.

Another Brazilian defender, Felipe Luis -- pictured center -- rejoined Atletico Madrid for $16.4 million in July 2015 after just one year at Chelsea.

Goalkeeper Kiko Casilla, 28, returned to Real from Espanyol for $6.1 million in July 2015.

Belgian winger Yannick Ferreira Carrasco moved to the Vicente Calderón from French club Monaco for $18.7 million in July 2015.

Montenegro defender Stefan Savic cost Atlético $25.2 million in July 2015, when midfielder Mario Suarez moved in the other direction to Italian side Fiorentina.

Real Madrid's key signing of the January 2015 transfer window was Martin Odegaard (pictured right with Cristiano Ronaldo). The Norwegian teenager had attracted the attention of the world's biggest clubs.

Atletico brought prodigal son Fernando Torres back to Madrid on loan in January 2015, and the former Liverpool and AC Milan striker signed a permanent deal in August.