Red Bull is still facing an uncertain future as it has no engine for the 2016 season, with Ferrari and Mercedes having decided against a deal with the Milton Keynes team.

Honda has said the door is open for a deal, but McLaren is against the move, leaving Renault as Red Bull's only option, even though the team had earlier decided to part ways with the French manufacturer after a difficult season.

With no competitive seats available for next year, should Red Bull quit, Ricciardo could find himself without a drive.

NASCAR Sprint Cup star Dale Earnhardt Jr wrote on Twitter earlier this week that Ricciardo would have a drive available for him in any road course Xfinity series race if he wanted it.

The Australian remains confident he will be in F1 next season, but admitted Earnhardt Jr's invite was tempting.

"If not, Dale Jr invited me to do a NASCAR race next year, so I might take that up if I don't have an F1 seat," joked Ricciardo in Mexico.

"I like America a lot, so to live in America and race, still post-F1, could be interesting.

"Obviously I want to make sure I'm here next year, but if for whatever reason I'm not, it sounds like I might have an option."