IMSA has released the 20-car entry list for the upcoming Chevrolet Detroit Grand Prix at Belle Isle, with several top GTD squads opting to skip the Sprint Cup round.
The double-header weekend with IndyCar at the Michigan street course is one of two rounds on the 2021 calendar where GTD teams can only earn points going towards the WeatherTech Sprint Cup and not the overall championship.
Top Porsche squad Wright Motorsports and Pfaff Motorsports, as well as Magnus Racing with Archangel, are not entered for the 100-minute race.
GRT Grasser Racing Team and SunEnergy1 Racing have both returned to the class, resulting in a 12-car grid for GTD that also features the regular class field.
Elsewhere, six cars have been entered in the DPi category: the two Acuras from Wayne Taylor Racing and Meyer Shank Racing, alongside the three Cadillacs for Chip Ganassi Racing, Mustang Sampling and Whelen Engineering, with the lone Mazda completing the class.
Finally, both Corvette C8.Rs form the grid for an exhibition GTLM round, which will not go towards points for the full season.
The Proton Competition-operated WeatherTech Racing Porsche, which won the Twelve Hours of Sebring, is also absent. The German squad is unable to attend the Detroit event, as the race clashes with the FIA World Endurance Championship round at Portimao.