Robert Kubica: World champion Nico Rosberg working to help Pole return to F1

Nico Rosberg posted a photo of himself karting with Lewis Hamilton and Robert Kubica to reveal he was working with Kubica

World champion Nico Rosberg has joined Robert Kubica's management team and is working on securing the Pole a return to Formula 1.

Kubica has not raced in F1 since being left with partial movement in his right arm after a rallying accident in 2011.

Rosberg announced the arrangement on Twitter, posting a picture of himself in karting with Kubica and Lewis Hamilton.

"Excited to be working with Robert and his return to F1," said Rosberg.

"He and Lewis were the fastest I raced against."

Kubica added: "We have known each other since we were kids and he will be a great asset in my F1 comeback."

Rosberg, 32, retired after winning the world title with Mercedes last season.

Kubica has conducted three tests with the Renault team, including one in the 2017 car at the Hungaroring after the Hungarian Grand Prix.

Renault ultimately decided not to re-sign the 32-year-old, who raced for them in 2010, and will announce over the Singapore Grand Prix this weekend that they have recruited Spaniard Carlos Sainz to partner Nico Hulkenberg in 2018.

Renault team boss Cyril Abiteboul said there were still "question marks" about Kubica's ability to make a full comeback. He would not go into detail.

But Kubica is still pursuing a return and his manager Alessandro Alunni Bravi has said the driver had proved he could race in F1 in the tests.

There are few options remaining for Kubica on the F1 grid for next year as many of the seats are already full, and the other teams are wary having seen Renault turn him down.

But one option is a potential seat at Williams, who have a vacancy alongside the Canadian rookie Lance Stroll next year, having not decided whether to continue with Felipe Massa yet.