Cape Town - McLaren will confirm Carlos Sainz's 2019 team-mate before the end of September, so says chief operating officer Jonathan Neale.
McLaren are believed to be weighing up four candidates for the driver including the under-fire Stoffel Vandoorne.
Although he has failed to take the fight to team-mate Fernando Alonso this season, Vandoorne's exit is not yet guaranteed.
He, however, faces stiff competition from Sergio Perez, who spent one unsuccessful season with McLaren, Esteban Ocon and the Woking team's reserve driver Lando Norris.
The four will know before the end of September whether a McLaren seat awaits.
"We’ve announced that Fernando will be stepping down from Formula 1 and we announced the planned changeover to Carlos Sainz, who will join us from the beginning of 2019," Motorsport Week quotes Neale as having said during a conference call with McLaren investors.
"We’re in discussions about what we will do in the second seat and those announcements will be made in the third quarter."