I own Rocket League both disc and download format and I want to sell the disc, but I want to make sure it works before I sell it. When I put the disc in, it says "Do you want to switch to the disc version of this game? The downloaded version will be deleted."
I just want to know if that would completely get rid of my downloaded version or can I get it back?
Yes, if you choose to replace the digital version with the disc version, it will be deleted from the console. However, you will still be able to re-download the digital version (although you will need to delete the disc version).