Toro Rosso team principal Franz Tost believes Daniel Ricciardo has the edge over Jean-Eric Vergne at his team right now, but that that both would need an "exceptionally good" second half to the season to graduate to the senior Red Bull team next year.

With increasing speculation that Mark Webber will leave Red Bull next year, the likelihood of one of the Toro Rosso drivers replacing him is growing. Both are in their second year at Toro Rosso, but Tost thinks Ricciardo's extra experience at HRT in 2011 is currently giving him the upper hand.

"Well, performance is all that matters and you definitely can see that Daniel with 11 races more under his belt - which is more than half of a season - is probably in a better situation," Tost told the official Formula One website. "Right now he has the upper hand, which we have seen in Barcelona. But that is a snapshot right now. Generally I would say that both would fit into the Red Bull concept."

However, Tost said both drivers would have to up their games if they want to be considered for a Red Bull drive alongside three-time champion Sebastian Vettel in 2014.

"Both would have to demonstrate an exceptionally good second half of the season, because don't forget we are speaking about the world champions, so the requirement profile is quite different to being with a team like Toro Rosso," he added.

"But don't get me wrong, both are on a very good path and everything will depend on the next couple of months as to whether one of the two of them - should the need be there - qualify for Red Bull Racing."