Roman Reigns' recent medical issue is not expected to throw off WWE's plans for him very much. He will continue to receive a strong push heading into WrestleMania 31 and he is considered a likely candidate to win the 2015 Royal Rumble.
There is a good chance that we could see Roman Reigns, Daniel Bryan, and Dave Batista all make their returns to WWE programming at roughly the same time. Batista is expected to be back in time for WrestleMania 31 and there is some talk that this could end up being Batista's last run with WWE.
In the meantime, with Reigns being out of action, the plan is to have Dean Ambrose step up as one of the top babyfaces and pretty much take over Reigns' spot as the Number 2 babyface behind John Cena until Reigns returns to action.