Starting with handball at the age of 13 Andrej was found by RK Metalurg scouts and immediately given a 5-year contract. As one of the top prospects in his position he managed to seal his place in the Metalurg youth team and the youth categories of the national team. Since 2011 he played in every national meeting, having over 100 games for the NT, but eventually missed the 2017 World Men's Handball Championship due lack of play time in his club.