Won’t happen unless EA has a radical change of management, Frostbite is basically their internal engine for all their now (well, they’re trying to get it into every studio they own). It’s basically like Snowdrop for .
Hell will probably freeze over sooner than a public SDK for Frostbite. I wouldn’t make the switch anyway, based on what I’ve heard of it it’s a mix of code from about 40 different by now. Plus as developers we all know how much everybody hates EA, I wouldn’t trust them not to screw me over given their track record!
Source: Programmer with 12 years EA Experience stood behind me 