Sainz could replace Ricciardo at Red Bull

Carlos Sainz Jr has been earmarked as a potential replacement for Daniel Ricciardo if the Australian does not extend his contract with Red Bull. Team principal Christian Horner favours keeping Ricciardo on, but suggested Red Bull would prefer to promote from within if he leaves.

Ricciardo's future was a hot topic of discussion during pre-season testing in Barcelona.

Talks over a new deal are expected to commence next month, with Red Bull advisor Helmut Marko also confirming a deadline has been put in place for negotiations to finish by.

Having won five grands prix in four seasons after joining the then-constructors' champions in 2014, Ricciardo is reportedly keen to find a seat that will give him the best chance of challenging for the title.

Both Ferrari and Mercedes have been linked with a move for the Australian with Kimi Raikkonen and Valtteri Bottas only contracted to the end of 2018.

Sainz has been a member of Red Bull's junior program since 2010 and raced for Toro Rosso from the 2015 campaign up until his loan move to Renault late last year, which extends across the 2018 season.

He missed out on a promotion when Max Verstappen replaced Daniil Kvyat in 2016, but Horner suggested he would be at the front of the queue if Ricciardo departs.

"Daniel's contract expires at the end of this season and our intention is to have him with us in the future," Horner told CNN Sport of the Australian.

"The plan is to continue with the line-up that we have now, but if that isn't possible, we have other good alternatives.

"We have good drivers in the junior program and, in addition, we still have Carlos Sainz under contract, although he is now with Renault."

Sainz has 60 F1 races under his belt, securing a best finish if fourth place in last year's Singapore Grand Prix.