Realistically, only Haas and Alfa Romeo have seats available for next season as Mercedes - given Lewis Hamilton has yet to extend his deal - Red Bull and AlphaTauri are highly unlikely to tap into the free-agent market.
"Everybody is considered who is on the market," Steiner said when quizzed about 2021.
"We lay everything on the table and then we see what we want. It’s a principle question [of] what we want to do.
"Do we keep the drivers we have got, do we want experienced drivers, do we want to start with young drivers, do we do a mix of it? Everything is on the table. Nothing changes.
"The table gets fuller and fuller by the day, at the moment, which is a good thing because then you have a choice. And choice is always good."
Steiner, who said he will "discuss with Gene" Haas before making a decision on who to pick, revealed the long list of candidates alongside Grosjean and Magnussen who have been with the team since 2016 and 2017 respectively.
"Close to 10!" added Steiner. "It’s amazing who is around at the moment. That’s why you see me very calm.
"There are only 20 seats and we’ve got 10 potential people which could do the job, which is good. Two of 10 we’ve got already [Grosjean and Magnussen]. So you’re down to eight."
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