It's probably nothing. It's almost certainly nothing.
But what if it isn't?
UK retailer SimplyGames have listed God Of War 4 for a December 2015 release, and seem to be accepting pre-orders at the time of writing. Credit goes to HUKD member and prolific deal-finder FantasyDeals for the spot, and for tipping me off.
Normally it's the sort of thing that I'd dismiss out of hand, since we've seen similar listings come to nothing before, but the December 2015 release window is interesting. After all, Sony have just lost one of their big Christmas games following Uncharted 4's delay.
Seeing as Sony Santa Monica are reported to be working on a new God Of War, the timing would seem rather convenient. Either way, we'll find out in due course.