Electronic Arts has registered the domains for Battlefield 13 all the way through to Battlefield 20.
What this means is that EA now owns Battlefield.com, Battlefield2.com - Battlefield9.com as well as Battlefield13.com - Battlefield20.com. Interestingly Battlefield10.com - Battlefield12.com are owned by other parties.
This is no doubt just to protect the companies interests. We're pretty sure there won't be a Battlefield 20 anytime soon.