"I still see it as mainly me or Kevin," the Briton told reporters at the Mexican Grand Prix on Thursday when asked about other candidates being touted for the slot alongside Germany's Nico Hulkenberg.
Manor's 20-year-old French rookie Esteban Ocon has also been mentioned as a possibility for the only remaining seat at a manufacturer team.
Ocon, the former Renault reserve, is contracted to Mercedes but has strong links with the French team's boss Frederic Vasseur from the GP3 junior series. He said Mercedes was managing his career.
Palmer felt he still had the chance to make his case in the remaining three races and was confident he would still be in Formula One next season even if Renault decided on someone else.
"I think the reason the decision has been delayed is that it's not clear at the moment who is going to take the seat," he said. "I have other options as well, I'm not only focused on Renault.
"Renault is the main target, I also think a decision is not that far away although you never know, but I would be foolish not to be looking elsewhere as well."
One of those options would be Hulkenberg's vacant seat at fourth-placed Force India, although there are a lot of other interested parties, or Sauber.
Palmer said that the struggling Swiss team, set to finish last this season and yet to score a point, was not his main alternative focus but could become a target "further down the line maybe".
"I think I have a reasonable chance to be here ... I'm pretty confident of being on the grid next year," he said.
"Hopefully it's going to be here and I can show what I can do enough. If not then I am pretty confident of being on the grid elsewhere."
(Editing by Peter Rutherford)
