Forwarding VIP question

I think there is some missing information. There is no default route on the F5? If not, how is it routing traffic back to clients currently? I am under the assumption, based on the question, that the only thing changing is that SNAT is being removed. If that is the case, then serves pointing at the f5 floating ip as their default route will suffice. But it sounds like I am missing some of the configuration and architecture details.