A product of
Universidad Católica, Rojas took part of the
Chile under-17 squad in the
1993 FIFA World Championship at the age of fifteen, where they reached the third place. Due to this achievement, the players were given some state benefits in education and housing. He stayed with Universidad Católica until 1997 and switched to
Magallanes in the same year. The next year, he moved to Mexico and joined
Querétaro. Back in Chile, he played for
San Luis de Quillota and
Ñublense in 1999 and 2000, respectively. In Ñublense, he coincided with
Nelson Garrido and , both former fellows in Chile U17. After trying to sign with another club, he retired from football due to the fact that he lost the excitement, according to himself. ==Personal life==