Mazepin has been undertaking an extensive private testing programme with Mercedes for the past two years, helping his preparations to step up to F1.
The Russian driver secured an F1 superlicence by finishing fifth in this year's F2 championship, and will graduate with Haas next year.
But Haas is currently addressing an incident involving Mazepin after a video of him groping a woman's chest was uploaded to his Instagram account earlier this week.
Haas called the incident "abhorrent", with team principal Gunther Steiner telling Motorsport.com on Thursday that it was taking the matter "very seriously".
Mazepin issued a public apology and said he had to "hold myself to a higher standard as a Formula 1 driver".
It was thought that Mazepin would form part of Mercedes' line-up for the test d