When revealing its all-new turbo V6 'power unit' for next year near Paris on Monday, Renault's Jean-Michel Jalinier said he "definitely" expects more engine makers to enter F1 under the 2014 rules.
"That's why the number of our customers will fall in the future," he is quoted by German website motorsport-total.com, "because there are more competitors."
Honda, the Japanese marque that pulled out of F1 at the end of 2008 due to the global financial crisis, could be one such competitor.
The German-language Speed Week reports that Frenchman Gilles Simon, Ferrari's engine boss during the ultra-successful Jean Todt era, could already be working with Honda.
After leaving Ferrari, Simon worked for the FIA, but most recently he has been designing a turbo V6 for Craig Pollock's intended 2014 F1 supplier Pure.
But with Pollock's plans now collapsed, Speed Week reports that British sources suspect the newly UK-based Simon could be working on a F1 engine for Honda.
For its last F1 foray, Honda was based at Brackley, which is now the headquarters for Mercedes' similarly Ross Brawn-led works team.