Erasmus started his elite rugby career with the Free State during the 1994 Currie Cup. By the turn of professionalism in rugby union in 1995, Erasmus continued to develop as a leading loose forward for his province, and was selected for the Free State's debut season in the 1997 Super 12. By July 1997, he had been called up for national duties with the Springboks ahead of the 1997 British Lions tour to South Africa. With the series already won by the Lions ahead of the third test, Erasmus made his test debut on 5 July in Johannesburg, which the home side won 35–16. In his second match for the Springboks, on 23 August that same year, Erasmus played Australia, starting at flank, and scored a try, with South Africa winning 61–22 in Pretoria. Erasmus featured in 15 of the 17-match consecutive win streak the Springboks recorded between 1997 and late 1998. Had it not been for a 13–7 defeat by England on their 1998 tour, the Springboks would have completed a first Grand Slam tour since their 1960–61 tour. During that time, South Africa secured their first Tri Nations title in 1998, with four from four victories.