Rio Haryanto's management team is still working on a plan to keep the Indonesian in F1 despite losing financial backing from Pertamina.
The energy company announced on Tuesday that it was ending its sponsorship of Haryanto, who became the first Indonesian F1 driver last year.
Haryanto competed with Manor in the first 12 races of the 2016 season, but lost his drive to Esteban Ocon after the summer break for failing to meet his contractual obligations.
With Pascal Wehrlein set to occupy the second seat at Sauber, Manor remains the only option for Haryanto to race in F1 next year.
Despite the setback of losing the Pertamina backing, Haryanto's manager Piers Hunnisett did not rule out the Indonesian retaining a role in F1.
"We are still working on a plan to keep Rio in Formula 1," Hunnisett told Reuters. "People in the Formula 1 world felt he did a good job and he deserves to be there.
"Obviously, we were hoping to move into a team like Sauber - that was the plan but things are going to slow down a little bit," Hunnisett added.