Although a lot still hangs on Red Bull's prevarications over Mark Webber's replacement for 2014, the identity of whoever takes over from Daniel Ricciardo is not as clear cut as it may seem.

With the one Australian expected to replace another in Milton Keynes next season, Red Bull prot?g? Antonio Felix da Costa had been seen as the natural successor to Ricciardo, having earned race reviews for his few test outings in the top flight. However, with the Portuguese seeing his World Series by Renault campaign blighted by poor performance, other names are beginning to creep into the frame.

While Steve Robertson's discussions with RBR boss Christian Horner were thought to centre on Kimi Raikkonen, it is no surprise to see GP2 frontrunner Felipe Nasr's name cropping up in connection with Toro Rosso, with the Brazilian sharing Robertson's management expertise with the 2007 world champion.

According to Auto Motor und Sport, which cites Brazilian sources, Nasr's consistent season - which sees him leading the pursuit of GP2 points leader Stefano Coletti heading into the final third of the season - could see him leap-frog da Costa in the race to partner Jean-Eric Vergne, who is expected to retain his seat at STR for 2014.

The Brazilian is expected to tout backing from current GP2 sponsor Banco do Brasil when it comes to looking for a drive in the top flight next season, and would not be short of suitors, particularly if he manages to overhaul the mercurial Coletti.

Nasr's claim to an F1 place could also be enhanced by the precarious nature of compatriot Felipe Massa's position at Ferrari. While team boss Stefano Domenicali has expressed his preference for an unchanged partnership with Fernando Alonso, there are doubts whether Massa will be retained and, if he is dropped, whether he will decide to walk away from F1 altogether, having claimed that he has no intention of driving for anything other than a front-running team. Massa is currently the only Brazilian driver in F1....

Should Nasr wind up at Toro Rosso, meanwhile, it would see the British F3 champion come full circle, having apparently been offered the chance to join Red Bull's development scheme back in 2011. He declined the opportunity in favour of aligning with Robertson.