Allan McNish has admitted he is disappointed that Audi will not be racing at this season's Sebring 12 Hours, an event it has won for nine of the last 10 years.
Audi did not mention Sebring when it announced its 2010 program last month, as the manufacturer did not believe it had time to convert its R15 to the revised Le Mans regulations ready for the mid-March race. A bid to run an interim car in the American Le Mans opener was vetoed by main rival Peugeot last month.
"Sebring has historically been the Le Mans preparation for us," said McNish at the AUTOSPORT International show. "Even though it is part of the ALMS, even when we were doing the full championship over there, it was a separate crew, separate team of engineers, mechanics who ran Sebring because it was linked to Le Mans and it was our Le Mans preparation.
"This year, because of the late change of the ACO regulations, we basically had to dump quite a lot of our development work and start again, which means the car is not going to be ready in time for that particular race. We had the option to run an interim car, but one of the competitors basically did not agree to that, so we are not in a position to do anything about it.
"It is disappointing because I think the 180,000 fans who front up at Sebring got a titanic battle in the last few years and would have had again in 2010."
Audi is still expected to hold an endurance test at Sebring, even though it will not contest the race itself.
Although Audi beat Peugeot at Sebring last year, the French squad turned the tables in the Le Mans 24 Hours and ended Audi's winning streak. But McNish says his team has learned from that loss and will be harder to beat in 2010.
"It's actually quite an exciting program this year because we obviously have the fourth year of the direct head-to-head banging session with our French friends," he said. "We have an updated car and we've understood quite a lot of the reasons that we missed it all at Le Mans. That loss has fired everybody up quite considerably. It has been quite a good thing for everybody, a shake and reminder."
As well as Le Mans, Audi will also contest the new Intercontinental Cup, which kicks off with the a 1000km event at Silverstone, and the Spa round of the Le Mans Series.