DTM boss Gerhard Berger has revealed the series is willing to let independent teams compete in 2019 following the withdrawal of Mercedes at the end of this year.
Mercedes will contest its final season in 2018 before leaving to focus on its new Formula E project, which would leave the series with only BMW and Audi competing in the DTM in 2019.
Berger has expressed his desire to open up the championship to non-manufacturer entrants in future to make it more sustainable, amid rumours Mercedes' current works team HWA could remain in the series running unbadged cars from the manufacturer.
"A fully manufacturer-based system, as we have currently, is not good, and the participating manufacturers are aware of that," Berger told the German press agency DPA.
"If HWA needs other projects, the option of continuing to run DTM cars would be a nice solution.
"No other company has more experience and expertise in the DTM than HWA.
"The cars exist, only the engine changes [from normally aspirated V8s to four-cylinder turbos] in 2019.
"Sponsors would have to be found to finance it, but that would be feasible."
Mercedes motorsport boss Toto Wolff said the Stuttgart manufacturer would not object if HWA was able to find a sponsor to allow it to run its C63 DTMs in future.
"We have decided against the DTM as a platform, and that's the way it is," Wolff, who is a former shareholder in HWA, told Autosport.
"However, should HWA find a partner with whom it would like to remain in the DTM as an independent operation, we would not put any obstacles in its way."
Is HWA a realistic option?
The main sticking point for HWA remaining in the DTM after this season is the man whose initials give the company its name: Hans Werner Aufrecht, the former ITR chairman.
Aufrecht, 81, was replaced in his role by Berger at the end of the 2016, a decision that is said to have played a role in Mercedes' decision to announce its withdrawal from the series in July 2017.
So far, Aufrecht has shown little interest in helping out his successor Berger, and it appears more likely he will start his own touring car series in 2020 with the FIA, after the governing body's two-year deal to operate the World Touring Car Cup with TCR rules expires.
Berger is also understood to have brokered talks between HWA and prospective new manufacturers, such as Hyundai, Kia and Volvo, but so far to no avail.
The pressure is on Berger to find a solution quickly, as Audi is reported to be considering pulling the plug on its DTM programme if no new manufacturer can be secured by June.