The son of two-time World Rally Champion Carlos Sainz is edging closer to a Formula 1 seat for 2015.
19-year-old Carlos Sainz Jr is currently competing in Formula Renault 3.5, the top tier of World Series by Renault and the same category that McLaren rookie Kevin Magnussen won last year on his way to F1. Sainz Jr has since replaced Magnussen at the DAMS team and leads the standings heading into the championship's Monaco Grand Prix support race, having taken two wins, three pole positions and three fastest laps from the opening four races.
The Spaniard is part of the Red Bull Junior programme that has launched several drivers into F1, including Sebastian Vettel, Daniel Ricciardo and the current Toro Rosso line-up of Jean-Eric Vergne and Daniil Kvyat. He has already tested F1 machinery during last year's young driver test, and is now on course to run during a grand prix weekend.
"He is on the right track," confirmed Toro Rosso boss, Franz Tost. "The season has just started and there are a couple of good drivers in the World Series and we want to see how they develop during the season.
"But Carlos is doing a good job. If it continues I am sure he will sit in a Toro Rosso in a test or on a Friday.
"It really depends on the driver," continued Tost. "He is the one who steps on the gas. I always tell the drivers 'It is you who decides your future, not us'. Last year at this point I was sure Antonio Felix da Costa would be driving for us. I would not have bet that Kvyat would be instead."
Kvyat was a surprise addition to the F1 grid, but has proved extremely impressive during his opening five grands prix. With the Russian adapting so well, Sainz Jr's chance would come at the expense of Frenchman Jean-Eric Vergne, who has shown only flashes of class since debuting in 2012.
Though Vergne is known to have support within Toro Rosso - particularly from team principal Tost - the ultimate decision will come down to Red Bull advisor Helmut Marko, who is unlikely to give the 24-year-old a fourth season to impress in F1.
Current Red Bull drivers Vettel and Ricciardo both raced for the Toro Rosso squad before being promoted to the 'senior' team.