SPIELBERG, Austria — Sebastian Vettel is prepared to walk away from Formula One for good if he doesn't get a convincing offer for next season.

The four-time F1 champion will leave Ferrari at the end of the year after failing to get a new contract. He faces an uncertain future with only limited options available for 2021 and has not started discussions with other teams. The truncated season starts Sunday at the Austrian Grand Prix.

"I want to make sure I make the right decision for myself and my future. I have a very competitive nature; I've achieved a lot in the sport and I'm motivated and willing to achieve more," Vettel said Thursday. "To do so I need the right package and the right people around me, so that's what I'm looking out for at the moment. If the right opportunity should arise then I think it's quite clear. If that's not the case I probably have to look out for something else."

Unlike two-time champion Fernando Alonso, who is open to an F1 return next season after quitting following the 2018 campaign, Vettel said his possible exit from the sport wouldn't be temporary.

"I am of the conviction that if you are prepared to shut the door then you should be prepared to shut that door and not expect it to open again," Vettel said. "You have to be aware of the decision you are making, that's also why I am not rushing into anything. The next weeks and months will probably bring some more clarity."

One possible option for Vettel is Renault, which is losing Daniel Ricciardo to McLaren next year, but Alonso is also being considered by the French team as his replacement. 

The other option, seemingly unlikely, is for Vettel to replace either Valtteri Bottas or six-time F1 champion Lewis Hamilton at Mercedes. Both are out of contract at the end of the year but expected to sign new deals.

Vettel was outperformed by teammate Charles Leclerc last season, even though it was Leclerc's first season with Ferrari and only his second in F1. 

While the 22-year-old Leclerc was offered a new five-year contract until 2024, Vettel and Ferrari team principal Mattia Binotto could not agree on a new deal.

"It was obviously a surprise to me when I got the call from Mattia, when he told me there was no further intention from the team to continue together," said Vettel, who turns 33 on Friday.

The increasing tensions between Vettel and Leclerc last season culminated in a crash at the Brazilian GP in November. Leclerc overtook Vettel cleanly and Vettel tried overtaking him back with a risky move, sending both cars out of the race and infuriating management.

Vettel said he will obey team orders this season if he is asked to let Leclerc past him, but he has no intention of reigning in his competitive edge.

"Should the situation arise and make perfect sense then you'd expect both drivers to help each other out. I don't think that has anything to do with the fact my contract expires," Vettel said. "But at the same time you're racing for yourself, so I'm not trying to make Charles' life easier on track in terms of waving him by."