Born in San Miguel de Tucumán, Argentina, Pereyra began his career within the youth academy of River Plate; due to his origins, he was given the nickname "El Tucumano". His professional career began in 2009 when he made his River Plate debut in the Argentine Primera Division against Huracan at the age of 18. After featuring on 43 occasions for River, Pereyra transferred across the Atlantic Ocean, swapping continents, as he joined Udinese Calcio ahead of the 2011–12 Serie A season.