Lewis Hamilton started his second full test for McLaren on Wednesday, with the Formula One team still to decide their line-up for next week's season-ending Brazilian Grand Prix.
The 21-year-old Briton is a leading candidate to replace Kimi Raikkonen at the Mercedes-powered team when the Finn joins Ferrari at the end of the year.
Hamilton could be drafted in for the Interlagos finale, although team boss Ron Dennis has sounded unconvinced by the merits of such a debut.
Dennis told reporters at last weekend's Japanese Grand Prix he did not know who would race with Raikkonen in Brazil and no decision would be taken until after the tests at the southern Spanish Jerez circuit.
Spaniard Pedro de la Rosa, 35, has started the last seven races following Colombian Juan Pablo Montoya's departure for NASCAR and is also in Jerez.
Champion in his first year in GP2, the support series considered a feeder to Formula One, Hamilton has been backed by McLaren for the past decade and impressed at a Silverstone test last month.
MORE MILEAGE
"The aim is to give him [Hamilton] more mileage at a different kind of circuit," Dennis said of the latest outing.
"I have to stress he's not going there [Jerez] with a view to demonstrating to us something that would [make us] say he's going there [to Interlagos].
"He will run for a test and there's all sorts of things that are relevant, his ability to change settings on the car without dropping pace and all the other things you have to know how to do," said Dennis.
McLaren are assured of third place in the championship, with Ferrari and Renault out of reach in a private battle for the constructors' title.
But they will be determined to win in Brazil, with the team otherwise condemned to their first season in a decade without a victory.
"When we discuss it and think it through, there's not a massive upside to him [Hamilton] racing in Brazil," said Dennis.
"Why throw anybody in at the deep end just to satisfy people who would like to see how well he would do? This is a hero to zero sport and why put anything at risk?"
The team said Hamilton and De la Rosa were running through set-up and tyre evaluation programmes for Brazil as well as 2007 development issues.
