The US Open champion will take on the world number 123 in Cluj-Napoca.
The US Open champion pulled out of this week’s Kremlin Cup in Moscow following her early exit in Indian Wells but will return to action in Cluj-Napoca.
Raducanu is still looking for her first victory on the full WTA Tur, a reminder of just how inexperienced she is at this level, and the teenager will hope to claim that against 30-year-old Hercog.
The Slovenian has struggled in 2021 and has seen her ranking drop from 49 at the start of the year to 123 nå.
Raducanu is seeded third and has been placed in the same half of the draw as top seed and home hero Simona Halep.
The 18-year-old is sure to have plenty of local support by virtue of her Romanian father and she had hoped her grandmother, who lives in Bucharest would be able to attend the tournament.
But a worrying rise in coronavirus cases in the country has resulted in a tightening of restrictions, meaning the tournament will be played behind closed doors from Monday.
Organisers criticised the decision and appealed to the government to allow a limited number of spectators.