Hartley to race with number 39 on F1 debut
16 October 2017 – Brendon Hartley will race with #39 on his Formula 1 debut at the United States Grand Prix, taking up one of Toro Rosso's dedicated test/reserve numbers.
Hartley is stepping into the STR12 vacated by Pierre Gasly, who made his Formula 1 debut in Malaysia, and remained in the car in Japan, alongside Carlos Sainz Jr.
Toro Rosso initially confirmed Gasly and Daniil Kvyat this weekend's Austin event, but Gasly will instead race in the Super Formula finale, as he looks to secure the title.
With Sainz Jr. moving to Renault, and Gasly unavailable because of his Super Formula duties, Toro Rosso recruited Hartley to make his Formula 1 debut.
See also: F1's first double swap since 1994
Under Formula 1 regulations introduced in 2014, drivers are free to choose a number between 2 and 99 to carry throughout their career, with 1 reserved for the reigning champion.
Formula 1 teams are also given dedicated test/reserve numbers for use during each season, with Toro Rosso handed 38 and 39 for 2017.
Toro Rosso applied 38 to Formula 2 racer Sean Gelael, who has made several test and practice outings, and has now allocated 39 to Hartley.