Lotus Renault team boss Eric Boullier says he has no intention of giving Robert Kubica a car to prove his fitness in only to see the Pole jump ship to another team in 2013.

Relations between what is currently known as Renault and injured superstar Kubica have become increasingly strained in recent weeks.

At first Renault were adamant they were keeping the door open for the highly-rated Pole after the devastating rally crash that sidelined him for 2011.

But the team's deadlines to hear about his likely 2012 fitness kept passing with no word from the Kubica camp.

A Renault statement last week said he would not be ready for the start of the season, but Kubica's manager Daniele Morelli criticised it to the Italian press, saying the wording and sentiments were not what they had agreed - accusations that received short shrift from Boullier.

Now amid rumours that Kubica could be on the verge of committing himself to Ferrari for 2013, Boullier said he needed to hear more from Morelli, and was adamant that if Kubica wanted to come back with Lotus (as Renault will become next year), he needed to be fully committed to the team for more than just a handful of comeback races.

"We still have to sit down with Mr Morelli," said Boullier.

"The first thing is the first test and when Robert will be back.

"I need to understand if Robert can be back and what is Robert's commitment for the medium term.

"I will not bring a car and do a nice test for him if it turns out that he has already signed an option elsewhere."

Ferrari have long been suspected to have an interest in Kubica.

Their current lead driver Fernando Alonso both rates Kubica very highly and gets on well with him.

There has been speculation that Kubica could test his fitness using older Ferraris at the Fiorano test track or in the team's simulator, but team boss Stefano Domenicali rubbished the rumours.

The Italian insisted the Kubica talk was just part of the endless gossip around Ferrari's future driver plans.

"We've been speaking about drivers for Ferrari since February last year," Domenicali said when asked about the Kubica talk.

"Maybe next year we'll come back to Valentino Rossi..."