DTM and Formula E regular Frijns was due to contest the German endurance classic for the Car Collection Motorsport team, sharing the #3 Audi R8 LMS with Mirko Bortolotti, Christopher Haase and Markus Winkelhock.
However, ahead of Friday's third qualifying session, Audi released a brief statement saying that Frijns would take no further part in the weekend.
It added that the Dutchman was tested for COVID-19 and returned a negative result.
The #3 Audi was sixth-fastest in Thursday's first qualifying session, eight seconds shy of the pace-setting Lamborghini Huracan GT3, but slipped to eighth after the night session.
It's one of three works-supported entries in the top SP9 class, along with a car entered by reigning champion Phoenix Racing for Nico Muller, Frank Stippler, Dries Vanthoor and Frederic Vervisch, and a Team Land-run R8 LMS for Mattia Drudi, Kelvin van der Linde, Christopher Mies and Rene Rast.
However, the fastest Audi entry on Thursday was Phoenix's second car, the #15 entry shared by Michele Beretta, Jules Gounon, Kim-Luis Schramm and Frank Stippler, which was second-fastest, 3.915s off the pace.
#15 Phoenix Racing Audi R8 LMS GT3: Kim-Luis Schramm, Michele Beretta, Jules Gounon, Frank Stippler
Audi Communications Motorsport