Gene replaces Timo Bernhard, who has failed to recover sufficiently from his injuries following a testing crash in March.
"I’m very pleased with the steps I’ve managed to make during this time," said Bernhard.
"We’ve created a tight system of medical checks, so my progress has constantly been monitored. Unfortunately, there’s not enough time before the Le Mans 24 Hours to become 100 percent fit again.
"Le Mans is a world-class race that doesn’t allow any compromises. I only want to compete at this event in perfect physical condition. That’s why on the advice of my doctors and in close coordination with Audi I decided not to run at Le Mans this year."