Ferrari could bring 2016 Formula 1 engine upgrade to US Grand Prix

The Scuderia has four engine development tokens remaining and is weighing up the possibility of using the final four races of 2015 as a test bed.

The situation is complicated by the fact Sebastian Vettel still has a chance, albeit it slim, of winning this year's drivers' championship.

As Vettel and Kimi Raikkonen have both used up their allocation of four engines this season, following an update at Monza last month, any further change will incur a penalty.

When asked whether Ferrari planned to introduce an upgrade for the US GP, team principal Maurizio Arrivabene said: "We are thinking about it and we will tell you in Austin.

"Of course the situation with Seb now second in the championship is changing things a bit.

"But we have to do our calculations at home and look at what we have in our hands before taking any kind of decision."

The German moved up to second in the standings behind championship leader Lewis Hamilton but is 66 points adrift with a maximum of 100 remaining.

Should Hamilton outscore Vettel by nine points and Nico Rosberg by two at Austin later this month, he will win his third world title.

Vettel would still, however, be in a close fight with Rosberg for the runner-up spot.

With Raikkonen no longer in the championship fight, Ferrari could choose to only introduce the update on the Finn's car at Austin and take the penalty.

Raikkonen is a distant fourth in the drivers' standings, 12 points clear of nearest challenger Valtteri Bottas.

LEADING DRIVERS' STANDINGS: