Otto Rehhagel is currently in charge of the Bundesliga strugglers, but the 73-year-old's short-term deal comes to an end at the end of the campaign.
Rangnick, who stepped down as coach of Schalke last September citing exhaustion syndrome, is reportedly keen to return to management, although he claimed formal negotiations with Hertha would not take place until it is known which division they are going to be playing in next term.
He told Kicker: "There is contact with Hertha, but, as long as it remains unclear how things will continue on a sporting and structural level, there is no point in holding discussions."
The capital club have plenty of work to do to stay in the top flight. They lie second bottom, two points behind Cologne in the relegation play-off place, with two games of the season left.