Sebastian Vettel says he did not expect Ferrari's decision not to keep him after this season.

It emerged after Ferrari announced the German would leave that he had never been offered a new contract.

The four-time world champion, who turns 33 on Friday, said: "It was obviously a surprise to me when I got the call and Mattia [Binotto, Ferrari team boss] told me there was no intention from the team to continue.

"We never got into any discussions."

He added: "There was never an offer on the table and therefore there was no sticking point."

Vettel's Ferrari seat alongside Charles Leclerc will be taken in 2021 by McLaren's Carlos Sainz, whose position in turn will be filled by Daniel Ricciardo, currently at Renault.

That leaves Vettel currently without a contract for next season, with the four-time champion's realistic options limited to Mercedes and Renault.

However, Lewis Hamilton is expected to extend his stay at Mercedes and Valtteri Bottas, who is also out of contract with the world champions, says they have told him they are not interested in Vettel.

And Renault are currently not in a position to challenge the top three teams for victories and championships.

Vettel said he was "motivated" to continue in 2021 but had not yet made "the right decision for myself and my future".

"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 is quite clear. If that's not the case, then I probably have to look out for something else."

Vettel also refused to commit to supporting Leclerc on track should he be asked to do so by Ferrari this year.

"This year it's very difficult to answer," he said, "because we don't know what type of first season we will have ahead of us. We don't know yet how competitive we will be, etc.

"But surely should the situation arise, it would make perfect sense [to] expect both drivers to help each other out. I don't think that has anything to do with the fact that my contract expires and I'm going to leave the team.

"But at the same time obviously you're racing for yourself so you know I'm not trying to make Charles's life easy on track in terms of waving him by. I think we have been fighting each other in the past and we will continue to do so."

Leclerc, meanwhile, has admitted he expects Ferrari to struggle this season.

"It is going to be a very challenging season for us," he said. "We still have this question mark [about performance] and we have to wait for qualifying to see where we are, even though we are 99% sure we are not going to be as strong as we were last year."

Ferrari have been saying since pre-season testing that they were lagging behind Mercedes and on Tuesday admitted that they had decided to fundamentally change their design direction after discovering flaws with their 2020 car.

The first developments will not be seen until the third race of the season in Hungary in two weeks' time and Ferrari will do the two races in Austria this weekend and next with their car in pre-season specification.