According to a booklet from the IgroMir Expo 2018, which is a Russian computer and video games consumer exhibition, it shows the game along with the number “2019” listed at the top. Granted the booklet is in Russian, but it’s not hard to figure out that “2019” most likely refers to the game’s release.
It is possible that maybe a release in Russia could take place in 2019, but given that SEGA hasn’t really mentioned anything about a release yet, and with retailers such as Amazon (who are currently accepting pre-orders) still listing a placeholder date for the 31st of December, 2018, we wouldn’t be surprised if the game were to really launch in 2019.
We’re not sure what could be the cause behind the potential delay, but if you were eyeing the game then maybe you shouldn’t hold your breath. Team Sonic Racing will launch across all consoles which includes the PS4, Xbox One, and the Nintendo Switch.