The 30-year-old player currently plays at Croatian club HNK Gorica.
Sikošek represented the Slovenia national football team from 2016 to 2022.
Persepolis will most likely part ways with its veteran winger Vahid Amiri and Sikošek is a candidate to replace the player.
Persepolis is scheduled to meet Fajr Sepasi in the 2025-26 Iran Professional League (IPL) opening match next week.