He is well known to Simeone as the pair coincided in Argentinean club, Estudiantes de La Plata. One of the main reasons for his move to Spain is his desire to form part of the Argentina squad for the 2014 World Cup.
The weather means the Ukrainian league stops until March, leaving him little time to show that he deserves a place in the World Cup and his club gave him permission to leave in order to allow him to pursue that ambition.
He is well known as a player who is very effective to set pieces and that will add an extra dimension to Atletico's attacking options.