Audi scraps LMS program
"We will not participate in the LMS," he said. "We all have to face that the economy is moving and everyone has to put something into their pocket to save money.
"The LMS has grown quite significantly but you have to face the fact that to make the best out of less money, there is no choice but to cut parts of the program."
The Le Mans 24 Hours is, so far, the only confirmed outing for the R15 beyond the American Le Mans Series season-opener, the Sebring 12 Hours, in March.
But Ullrich says a decision about a tenth consecutive full ALMS campaign is still to be made.
"We are still in discussion about the American program," he said. "There has to be a board decision to do it, but we are all working on it very hard."