Robert Kubica's sponsor is not ruling out a change of teams for the struggling Polish driver.

Of the ten teammate pairings in 2019, no gap is greater gap than the one between Kubica and his impressive rookie teammate George Russell.

But Kubica, who returned to F1 in 2019 with permanent arm injuries after an eight year absence, has hinted that there is more to the gap than it seems.

"It's a combination of different things," the 34-year-old told Przeglad Sportowy.

"I have some influence on some, as in two or three races I could have been in front of him. But other things happened that did not depend on me.

"In addition, George Russell is one of the bigger talents of the young generation, with very high skills. He has said the car is better and better, but I don't want to comment on that. It is his point of view."

The implication is that Kubica may be alleging that Russell is getting the better material at Williams, whose car is clearly the slowest on the grid.

"I have never driven George's car so I cannot judge, but you do not have to drive to see some things," Kubica said.

"It can be said that we have sometimes driven in two different races, because the time difference on such a short lap as Canada, where there are seven corners, shows that there are two different worlds."

Kubica's current contract is for 2019 only, with an 'option' for 2020.

His sponsor, PKN Orlen, is not ruling out a move for Kubica.

"That is for Robert and Orlen," CEO Daniel Obajtek told Sportowe Fakty. "Everything is on the table and there are such possibilities.

"We often talk about this subject, and a lot depends on the direction Robert will take. After all, he has a good sense of the sport," he said.