Fittipaldi will prioritize his RLL program next year, but he still has the scope to retain his links with Haas, for whom he competed in the last two races of the 2020 season as a replacement for the injured Romain Grosjean.
With the IndyCar season ending on September 15, he will potentially be free for the final seven races of the F1 calendar, while also having some spare weekends earlier in the year.
With 24 events on next year's F1 schedule, many teams are splitting the reserve role, with Haas now potentially having the option to have Ferrari junior Oliver Bearman on hand as well.
"We have to figure that one out," said team boss Guenther Steiner when asked about Fittipaldi. "I was speaking with Fred [Vasseur] about what they are doing with reserve drivers for next year, but we haven't come to a conclusion.
"I don't think we'll lose him completely. As I said, we looked into it, what is possible, what is not. We know the calendars. We had a chat today about it.
"Also, how much testing, because in IndyCar they do more testing than we do here, how much is involved in that one. Pietro is part of the family and if you don't have him around you miss something."
Fittipaldi is keen to retain his F1 links despite switching his focus to the USA.
"I think it would be amazing to continue with Haas," he told Motorsport.com. "Because first, we've been together for so long. It would be going on to the sixth season.
"And we always do a really good job together in the testing duties, and trying to work on developing the car. I love doing that work for the team.
"And for me as a driver it's very useful as well. Because every year technology changes, and it's useful information that can help me in any series that I'm racing in.
"Obviously Guenther knows that the priority and the focus is 100% IndyCar. But that's what we're looking into now, to see what the possibilities are to continue as reserve and continue doing the testing duties for the team. So we'll know soon, but the intention is there."
Fittipaldi confirmed that the last part of the F1 season is his best chance to be available on a consistent basis.
"Because the IndyCar season ends early in September, from then until the end of the year, it's seven F1 races. Already there you have a third of the season. And then there's some races which probably would be easier, like the Miami GP, if I'm in the US.
"And being able to continue doing some testing duties, I think that would be important. So we're in the process of looking at that. But I think the intention is there to be able to do something.
"There's no rush to do it, and I don't see a reason why it wouldn't be possible. But I need to double check with the team, Rahal, and make sure that nothing clashes, and that they're comfortable with me doing it as well."
