The deal will run out in 30 June 2023.
Mrzljak signed a deal with Ufa in November as free agent. He scored four goals in 15 matches during RPL season, and three of these goals came in six games under Aleksey Stukalov.
Previously 28-year-old midfielder played in Croatia for Lokomotiva Zagreb and in Romania for Pandurii, Astra and Dinamo Bucharest.