Mrzlečki started his career at Mladost 2014, then played for Hajduk and Šibenik. He spent several years abroad playing for Belgianclubs Harelbeke, Lokeren, Mechelen, and upon his return to Croatia he played again for Bjelovar, Pitomača and Vrbovec. He ended his playing career in 2011 with a game in Suhopolje.