Sir Jackie Stewart has questioned the health of the 2012 US grand prix project.
A site east of the Texan capital Austin is scheduled to host formula one's return to America next November.
But there were reports of internal ructions within the organising body and circuit construction delays long before another US round, a street race amid the New York skyline, was announced for 2013.
Circuit designer Hermann Tilke, however, insists that Austin is on track for 2012, and the F1 Commission last Thursday re-confirmed the 2012 calendar as it was published by the FIA.
But the digital magazine Houston Culturemap quoted triple world champion Stewart as saying in India recently: "I am a little bit confused; there seems to be a sudden silence about Austin.
"I haven't heard a word about Austin for months now," he added. "I am assuming that it is still very much on, but you would have thought with only 12 months to go there would be something going on."