Sebastian Vettel should leave Red Bull at the end of the season and go to Ferrari, according to former World Champion Jacques Villeneuve.
Vettel and Red Bull dominated the sport after the German joined the Milton Keynes in 2009, winning four successive Drivers' and Constructors' Championships though.
Following the spate of rules changes that came into effect at the start of the season, Vettel has struggled to adapt to the new Red Bull and has been out-qualified and out-raced by his new team-mate Daniel Ricciardo several times this season.
According to Villeneuve, Red Bull are more focused on Ricciardo now and should a seat open up at Ferrari, Vettel should jump at the opportunity to join Scuderia.
"He's a four-time World Champion who has earned the titles won, but now Red Bull Racing is treating him like they were to Mark Webber," Villeneuve said during an interview with OmniCorse.it.
"They seem to have decided to focus only on Daniel Ricciardo. Now they want to "kill" Sebastian because the German is not able to give another image of Red Bull.
"Of course, he cannot stand one more season. Helmut Marko has now also started to criticise him. When you lose control of the team and the policy begins to have an ever-increasing weight, you're finished. Vettel is finished there, he needs to change team.
"Who said that the door is closed at Ferrari? I think that Fernando [Alonso] is tired of working for nothing. And it shows that he no longer had the joy of driving up to two years ago.
"He carried the team on his shoulders, while last year he gave up. He no longer has the strength to drag the team alone.
"I think that next year we will see a Ferrari in recovery and if Fernando will have the patience to wait he will derive the benefits, otherwise..."