Gunther Steiner has hit back at Haas reserve driver Louis Deletraz, who is upset that he was overlooked to replace Romain Grosjean this weekend in Bahrain.

The small American team has instead selected F1 legend Emerson Fittipaldi's 24-year-old grandson Pietro - the second official Haas reserve.

But Deletraz, a 23-year-old Swiss driver who is seventh in the Formula 2 standings, hinted on social media that Haas should have had more "respect" for him.

"Congrats Jack, Williams and Mercedes," he said after Jack Aitken was selected to replace the Mercedes-bound George Russell ahead of this weekend's Bahrain round.

"A choice based on pure performance. It's nice to see a team with respect to its drivers."

When asked about that comment, Haas boss Steiner reacted with frustration.

"I haven't spoken with him recently, but I saw that he is angry - and he's not the only one who is angry because they wanted that seat," he said.

"He is just one of them, so get in line. Pietro deserves it," Steiner added.

"I asked him to be here because I was worried about coronavirus, and so he came to be away from home for three weeks without any assurance of being able to race.

"There is no debate about this," he continued. "It was the plan that was on the table and we followed it. Besides, I don't have to ask anyone else who I should put in the car."

Steiner also played down speculation that Mick Schumacher might be a candidate to race next weekend in Abu Dhabi, as a limping Grosjean with heavily bandaged hands returned to the Bahrain paddock on Thursday.

Steiner insisted: "I want Romain to come back so I'm not thinking of anything else.

"I think he can end his time with us at that race, that's what I've talked about with him and I want him to end on a high note.

"We won't decide otherwise until someone tells us that he cannot race," he added.