Back in October, the German series announced a nine-round schedule with a 'TBA' venue on 3-5 June.
However, this date has been scrapped from the latest draft calendar announced on Thursday following the end of championship promoter ITR's agreement with Assen.
The move leaves the 2022 schedule with eight rounds - four in Germany and four at other European venues.
Portimao is still set to host the opening round of the season on 1 May, with Imola, Spa-Francorchamps and the Red Bull Ring the remaining non-German venues.
Assen joined the DTM schedule in 2019, replacing Zandvoort as the DTM's Dutch venue. It was unsuccessful in its attempts to renegotiate its contract with the series after its initial three-year deal expired.
Event promoter Lee van Dam commented: “Assen is an event that is not being organised by the race track, but rather by us as an external promoter.
“Because of the increased costs for the event as a result of the Covid-19 pandemic, we have tried to renegotiate our contract, but we haven’t found a solution that was acceptable to both sides and therefore we jointly agreed on how to proceed.
“We would like to thank everyone involved and the fans for their support and for three great years of DTM at Assen and we wish ITR all the best for the 2022 season.”
ITR’s managing director Benedikt Bohme added: “In extensive conversations, we have tried again and again to put the profitability into a proportion that would be acceptable for both parties. Eventually, we came to the joint decision to terminate the contract early.
"Here, I would like to thank Lee van Dam for the negotiations and for three very good events in Assen.”
For the DTM's second year of GT3 regulations in 2022, Porsche will be represented for the full season by 2020 ADAC GT Masters title-winner SSR Performance, following its cameo outing at the Nurburgring this year, and by Le Mans winner Timo Bernhard's Team 75 outfit.
Three-time series champion Rene Rast will also return to the series after a year in Formula E, having been confirmed at Abt Sportsline alongside 2021 championship challenger Kelvin van der Linde.
2021 DTM calendar
1 May Portimao
22 May Lausitzring (banked Turn 1)
19 June Imola
3 July Norisring
28 August Nurburgring
11 September Spa-Francorchamps
25 September Red Bull Ring
9 October Hockenheim
