For the last three years Frijns has combined his FE commitments with Envision Virgin Racing with a factory Audi drive in the DTM, scoring multiple race wins in both categories.
While the Dutch driver already has a contract with Envision for the 2020/21 FE season, he is yet to pen a deal to remain in the DTM for its first season under GT3 regulations.
But a fourth consecutive campaign in the German-based category now looks difficult to pull off, as he believes his FE programme may not allow him to complete a full season elsewhere.
The 2021 DTM calendar currently comprises nine rounds in Europe from late May to early October, while FE has so far only confirmed its Saudi Arabia opener - although the next batch of races are set to be announced at the end of this month.
“I still say, if I get the chance, I will grab it with both hands, but it is very difficult for myself to say anything at the moment,” Frijns told Motorsport.com when asked if he could race in both Formula E and the DTM in 2021.
“Everyone knows that Formula E is my priority. For the last two or three years, I have always been lucky that there has been no clash between Formula E and DTM. But now these calendars are changing because of COVID.
“They say from Formula E when the races have to take place, but that can change quickly. For example, the Santiago race has already been postponed. They now say that Mexico will be in June, but perhaps not. Maybe Santiago will be in June, maybe not.
“So I can't say to Audi, 'I want to drive DTM' if I then have to miss two, three or four races due to clashes with Formula E. That's why it is very difficult to say 'I'm going to drive DTM'.
“The fact is that Audi is very keen to keep me. They are very happy with what I have done and how I work with the team. That is not a problem, only the calendars are a problem. Audi can't really offer me anything in the DTM right now and neither can I [give them any guarantees], just because we don't know how many clashes there are.”
Robin Frijns, Audi Sport Team Abt Sportsline