Capcom never officially announced a localization of PS4 exclusive Deep Down for the western market. All we know is that it’s being considered, but at last something seems to be moving on multiple fronts.
The “Deep Down” trademark has recently been published in the US database, registered by Capcom itself (you can see a screencap of the search at the bottom of the post). A similar trademark appeared previously for the European Union.
Capcom also had already registered the domains d-down.com, .net and .org. While they still lead to a placeholder page, they have been updated very recently, on January the 1st.
With the PS4 heading towards its release in Japan, times seem to be mature for an announcement, and everything seems to be in place. Of course we should wait for the official announcement itself before getting too excited, but the cogs seem to be in motion.