In April 2013, he signed a 5-year contract with Portuguese club Benfica, joining at the start of the 2013–14 season.
[5] After playing for Benfica B in the Segunda Liga, he was loaned to Belenenses in January 2014 for the rest of the season.
Upon his arrival back to Benfica he was again sent out on loan, as he joined former club Cerro Porteño.
[12] On 22 July 2022, Rojas returned to Paraguay joining Sportivo Ameliano, after a failed stint at Metalist Kharkiv due to the start of the Russo-Ukrainian War.
[2] He played in 12 games and scored 3 goals for Paraguay U20s, with them coming at the 2013 South American Youth Football Championship and 2013 FIFA U-20 World Cup.