Kubica "didn't show his best" in first Williams try-out in 2017

Williams Chief Technical Officer Paddy Lowe insists that Robert Kubica's arm injuries are no longer a factor when he's racing, although the Brit did admit Kubica wasn't ready for a Williams seat when he first tested in 2017.

The Pole spent 2018 as the Grove-based team's reserve driver behind Sergey Sirotkin and Lance Stroll as Williams finished the year in last place in the constructors' championship. 

Now, with both Sirotkin and Stroll having left the team, Kubica has made the promotion, as he'll line up next to Formula 2 champion George Russell, his first time driving F1 competitively since 2010.

"It's never that easy to chose drivers on a technical basis," Lowe told Motorsport.com.

"And actually if you look in the past very often what they weren't picked on a technical basis, team principals were just sort of put a finger in the air and decide they like the look of somebody and then give them a job.

"So we went through a pretty careful process, and from that picked Sergey. I believe that was the right choice. But within that process I don't think [Robert] was able to show his best.

"And I think that's been disappointing to him all year, but I think 12 months later we've been able to see, get to know him better and see what he can contribute and how he can perform.

"So that also supported the decision that we made.

"I think, even as we've done it, the amount of data is quite limited. So I think, like many things in life you do the best for the data you have, and then you make a decision, and see how it works.

"We are 100% committed to both George and Robert, and once we become committed and they become 100% part of the programme and we work with them, they work with the car, then you know, that plays out, and we see where it takes us."

Kubica's capability of driving an F1 car has been questioned on numerous occasions after his horror-crash in 2011, but Lowe insists it's no longer a problem.

"It is clearly something we had to consider in the selection, because you can't pretend that is not an issue, or potential issue. But now we've made our decision and we are confident that Robert is absolutely top class and ready to return to F1.

"I don't even think about it any more, it is just not a factor.

"Robert is our driver, he's 100% competent, he is 100% committed, we're 100% committed and we'll just go with that. Maybe other people from outside may bring that up, but it is not even in our minds."