Andretti plan to run current drivers Colton Herta and Kyle Kirkwood alongside new signing Marcus Ericsson for next season.
Grosjean’s future is unclear, with the Frenchman revealing he’s in talks with other teams.
The ex-F1 driver said: “I cannot speak for what Michael Andretti is doing with the fourth car, but I do have other IndyCar teams that are talking to me,” Grosjean told NBC Sports. “I will land on my feet.”
Despite starting 2023 strongly, Grosjean’s form quickly tailed off, with a run of finishes outside of the top 10.
As a result, his relationship with Michael Andretti deteriorated, particularly after Grosjean’s attitude and temperament was questioned.
His Andretti career looks to be all but over, with the team currently lacking the necessary financing to fund a fourth car.
“That is correct, we are still very much noncommittal,” Andretti told NBC Sports. “We are working on a fourth right now. To be honest with you, we really don’t know what we want to do yet. We hope to have an answer by Laguna Seca.
“There are a lot of things that go into a fourth car, not just sponsorship. We have quite a few different options we are looking at and see what the best one is that works for us.”
With Grosjean’s IndyCar future in doubt, a full-time switch to sportscars could be on the cards with Lamborghini.