Born in
Posadas, at the Argentine province of
Misiones, Rojas played for
Argentinos Juniors at the same time as
Christian Dollberg in 1991. He moved to
Cerro Corá in the same year and participated in their campaign in the
Primera División. In 1992, he joined the larger
Club Libertad, where he secured a place in the first team, amassing over 50 league matches in three seasons. According to
Record, the fee for both was three million dollars. He made his debut on 12 September, in a 3–0 away win against
Santa Clara, and went on to play 30 games in all competitions, mainly as a right-back. However, in
2000–01, the signings of
Ivan Dudić on the right, and the breakthrough of
Diogo Luís on the left, severely diminished his playing time, so in February 2001, he was loaned to
River Plate. His pay-check there was a reported 500 thousand dollars, one of highest in the league. Initially, under
Américo Gallego, he could only play in the
Copa Libertadores due to his late arrival in the season. On 11 March 2002, he scored his only top tier goal, in a 3–0 victory of River over its main rivals,
Boca Juniors. After scoring that goal, he was nicknamed
vaseline. He would play for River for a further four years, retiring in 2007 after a brief spell at
Belgrano. After football, he became a farmer and moved back to his home-town. ==International career==