In an interview with IGN, Dan Greenawalt, studio head of Turn 10 Studios, clarified how Forza Motorsport 5 will work if your Xbox One isn’t connected to Xbox Live.
“So when you first boot up the game, we’re going to ask you to log in,” he explained. “And when you log in you’re going to get the Drivatars and you’re also going to get a whole bunch of content: tracks and cars. Our production schedule is such that we are putting them in as late as possible and that means making them free as downloadable content on Day One.”
In a nutshell, to play Forza Motorsport 5, you first have to connect online to download mandatory content day-one for free.