George Russell has labelled Mercedes reserve driver Frederik Vesti as a shock contender to join Cadillac for the 2027 Formula 1 campaign.

The American outfit is yet to confirm Valtteri Bottas as a team-mate to Sergio Perez - who signed a contract extension on Wednesday - for next year, with various contenders emerging.

Cadillac’s test driver Colton Herta is an option, despite his current lack of a superlicence and highly disappointing Formula 2 season, while outgoing Haas man Esteban Ocon is also available.

But Motorsport.com understands that the Frenchman is destined to become Aston Martin’s reserve, whereas Vesti is still gunning to make his official F1 debut since finishing runner-up in the 2023 F2 standings.

The 24-year-old has dovetailed Hypercar duties for Cadillac with his role at Mercedes, where he has completed seven FP1 duties, including Friday in Mexico, where he replaced Russell.

Frederik Vesti, Mercedes

Photo by: Steven Tee / LAT Images via Getty Images

Vesti finished third, 0.074s behind stablemate Kimi Antonelli and 0.733s off Ferrari pacesetter Charles Leclerc, thanks to a late soft-tyre lap after various long-run programmes.

“He did a really good job,” said Russell. “I know he's really fighting hard to be in with a shot potentially of the Cadillac seat, and I think he deserves his chance.

“He's put a lot of effort in working with our team, we all respect him very highly; most FP1 sessions that he's done, he's had the brunt of the work and not really getting performance runs in.

“So I think it was important for us as a team, and I said to the team, 'I want to ensure that he gets an opportunity to show what he can do, that's the least that we could do', so yeah that was nice.”

Vesti was left “extremely happy” after FP1, which is more than what can be said about Herta, who stood in for Bottas but finished bottom of the timesheet and 3.237s off the pace.

The former IndyCar star was also 0.970s behind 18th-placed Perez, but talk of him getting the Cadillac seat is intensifying as he is likely to qualify for a superlicence by contesting FP1 in Brazil next week.

Colton Herta, Cadillac Racing

Photo by: Alastair Staley / LAT Images via Getty Images

“I want to do the best I can for the team,” said Herta. “Every time I get in the car, I want to be in Formula 1 - that's the goal.

“That's why I'm over here doing this. Personally, I want to get there as soon as possible. A lot of discussions are happening and a lot of stuff is going on outside of what I can control.

“I'm just trying to do my best inside the car and hope that shows for something.”