Haas F1 turned down a request from Ferrari to place one of its young drivers at the team in 2018, according to team principal Guenther Steiner this week.
"We work very closely with Ferrari together on things but they respect our decisions," Steiner told RACER magazine. "Sure, they asked us if we can do something, and we said no. It's fine.
"I think we work with both of our drivers very well so at the moment for us there is nothing to be changed."
The team has already confirmed that it is sticking with its current driver line-up of Romain Grosjean and Kevin Magnussen for 2018.
"We know we have got these two drivers," said Steiner. "Sometimes you need to look after the long term, because next year is short term.
"We make our plans and try to plan as well as possible. When we signed these drivers we had to make the plans together. We need to be consistent.
"I think we are pretty stable and for sure the drivers are helping to grow the team," he continued.
"I cannot say if it would have been different if we had someone else in the car," he admitted. "We don't have the years of experience to say, 'With this guy we did better than that one.'
"We're only in our second year [in Formula 1] and sometimes you forget that," he pointed out. "It looks like we've been here forever now but we've not.
"Everything is new for us," he added. "While consistency sometimes goes against you – sometimes fresh blood helps you do better – we need to build a base. For that, consistency is important."
Ferrari is keen to get race experience for two of its academy drivers, Charles Leclerc and Antonio Giovinazzi.
Leclerc won the GP3 series in 2016, and last week clinched this year's Formula 2 title. He's made appearances at five Grand Prix weekends - four with Haas last season, and most recently in Malaysia with Sauber.
He'll have three more outing during the remainder of the season. It's thought likely he will join Sauber full-time in 2018.
Giovinazzi was runner up in the 2015 FIA European Formula 3 cChampionship, and was second again the following year in GP2. He made his Formula 1 race début at the start of the year in Australia, subbing for an unwell Pascal Wehrlein.
He also raced in China, and took part in free practice at Silverstone, Hungary, Singapore and Malaysia.
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