We’re awaiting an official confirmation.
The previously approved Lego Ideas Sonic the Hedgehog set is rumoured to release January 2022, with set number 21331, and a price of €69,99.
The rumour also alleges a brick-built Doctor Eggman and Crabmeat. Sonic is said to be the same figure released for the LEGO Dimensions set. The Green Hill Zone level will be represented with a loop, a bridge with three floating rings, a spring and a spike trap. Also rumoured to be included are palm trees and a model of Egg Mobile.
Until we get an official announcement from the LEGO Group remember to treat this all with a pinch of salt.
Source: Brick Fanatics