Former Formula 1 driver Mario Andretti has said that George Russell has got some big shoes to fill in replacing Valtteri Bottas at Mercedes.

The Silver Arrows have a new driver line-up for 2022 with Lewis Hamilton, providing he doesn't make a shock retirement announcement, set to be joined by compatriot Russell next to him in the garage.

Indeed, it's the first driver change Merc have had since the start of 2017, which was enforced after Nico Rosberg retired as champion at the end of 2016.

Since then, Bottas has helped Mercedes become eight-time Constructors' champions but he never really managed to mount a serious challenge in the Drivers' fight, with Hamilton either proving too good or the likes of Max Verstappen carrying more of a threat.

Even so, Bottas proved a race winner and pole position sitter throughout his time at Mercedes and was labelled by Hamilton as 'the best teammate ever,' underlining his strong capabilities behind the wheel.

Certainlty, the Finn's speed at times was very good at Mercedes and Andretti is under no illusion that it will be tough for Russell at his new team, as he has 'some huge shoes to fill:'

"He has some huge shoes to fill! Not only vis-a-vis Lewis, but also vis-as-vis Valtteri, who was a strong, valuable teammate," the 1978 World Champion told Racing News 365 in an interview.

"We have seen what George did in Bahrain, on a one-off situation, so you would expect that he will show really strong [performance].

"But we always wait to see. You can draw a lot of conclusions, but until it's proven... Sometimes it's a one-off that really works out and then when you're really in there it becomes a little more difficult."

Russell will know what sort of challenge lies ahead but, make no mistake, he will feel as though now is the time for him to start making waves at the front of the grid after a few years with the Williams team towards the rear of the pack.

So far in his time in F1, Russell has managed to impress with his speed and consistency despite being in equipment shy of being able to deliver regular points finishes, and under the guidance of Mercedes he has now worked his way to a potentially championship winning car.

A champion at lower level formulae, Russell knows how to compete at the sharp end, and it'll be fascinating watching him do exactly that this year.