Alexander Albon is apparently now the favourite to race alongside F1 returnee Daniil Kvyat at Toro Rosso next season.
The British-Thai F2 racer's chances of joining the F1 grid in 2019 were given a massive boost following reports that Red Bull motorsport boss Helmut Marlo is in talks with Nissan to free Albon from his 2018-19 Formula E contract with the team.
Nissan will likely drive a hard bargain however as the Japanese outfit had committed to a multi-year deal with the 22-year-old for him to race in the all-electric series alongside team mate Sebastien Buemi.
Given the ongoing negotiations, Albon did not take part in Formula E's opening day of pre-season testing in Valencia on Tuesday.
Albon was initially backed by Red Bull in karting and Formula Renault, but was dropped from its young driver programme in 2012.
However, the good results he achieved on his own in the junior formulae and his competitive 2018 season in F2 with DAMS, coupled with a void in Red Bull's driver programme, decided Marko to have another look at the young charger.
Albon's subsequent promotion to F1 - should it come to pass - would see him join Lando Norris and Geiorge Russell among Grand Prix racing's rookies for 2019.