Ferrari Formula 1 junior Charles Leclerc will drive for Sauber in four free practice sessions this season.
The Swiss team plans to run the Formula 2 championship leader in FP1 in Malaysia, the United States, Mexico and Brazil.
It is understood Sauber has yet to decide which of Marcus Ericsson and Pascal Wehrlein will have to make way.
Leclerc is unavailable for the Japanese GP because it clashes with the F2 race at Jerez, but he may drive in FP1 in Abu Dhabi depending on the state of play in the F2 championship.
The 19-year-old previously completed four FP1 sessions for Haas last year, driving in Britain, Hungary, Germany and Brazil.
Leclerc has said he is unsure of his plans for next year but hopes to make his F1 debut with Sauber next season.
Sauber has yet to announce its 2018 driver line-up, but Leclerc is believed to be top of its list for one of the seats.