(Reuters) - Four-times world champion Sebastian Vettel recognised on Thursday his Formula One career could be over at the end of the season.
The German is starting his final year with Ferrari, with Spaniard Carlos Sainz already signed from McLaren to take his place at Maranello.
Champions Mercedes and fifth-placed Renault still have vacancies, on paper at least in the case of the former who have Valtteri Bottas and six-times world champion Lewis Hamilton out of contract at the end of 2020.
Mercedes could, however, opt to continue unchanged with Hamilton looking sure to stay and add to his impressive list of records.
Vettel said ahead of the season-opening Austrian Grand Prix that he had yet to have any real contract discussions with other teams.
"Obviously, I want to make sure I make the right decision for myself and my future. I think I have a very competitive nature, I have achieved a lot in the sport," he said.
"I’m motivated and willing to achieve more. 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 it is quite clear. If that’s not the case then I’ll probably have to look out for something else."
Vettel, 32, recognised there might be no coming back if he did have to walk away -- even if Spain's double world champion Fernando Alonso, who left the sport in 2018, is tipped for a comeback at Renault.
"I am of the conviction that if you shut the door then you should not shut it in the expectation that it will open again," said Vettel.
"You have to be aware of the decision you are making, that´s also why I am not rushing into anything."
(Reporting by Alan Baldwin in London, editing by Ed Osmond)