Charles Leclerc has withdrawn from Haas Formula 1 team Friday practice duties at the Abu Dhabi Grand Prix to prioritise his GP3 title bid.
Ferrari protege Leclerc was scheduled to drive in five grand prix practice sessions for Haas this year alongside his ART Grand Prix GP3 campaign.
He participated in the opening sessions in Britain, Hungary and Germany, and then swapped a planned Malaysia outing for Brazil.
Abu Dhabi was scheduled to complete his programme, but the adjusted timetable has precluded this.
Whereas at European F1 rounds GP3 action does not begin until late on Friday afternoon, the need to lean the F1 sessions towards the evening in Abu Dhabi means an unusual schedule.
Leclerc would have had to go straight from F1 practice into GP3 qualifying, and felt this would be unwise.
"A really hard decision to make but I won't be driving in Abu Dhabi during free practice one with the Haas F1 team because of the timetable," Leclerc wrote on his Twitter feed.
"I want to be 100% focused on my GP3 title.
"Doing the FP1 would have meant I had to jump from the F1 straight into GP3s qualifying."
Leclerc heads into the GP3 finale with a 31-point championship lead over ART team-mate Alexander Albon.
Haas team principal Gunther Steiner said in Brazil last weekend that a decision over whether Leclerc stayed involved in 2017 - when he is expected to race in GP2 with a leading team - would be taken after the Abu Dhabi weekend.
"He did a good job," said Steiner.
"He is a Ferrari development driver. If they want to keep on developing him we are happy to speak with them because we are happy with the job he did. No problem there."