Wladimir Klitschko is likely to return in March 2014 for his next defense of the WBA, IBF, and WBO world heavyweight titles, according to a repot at BoxingScene.com.
As far as opponent, Kubrat Pulev is the most interesting fight left for Wladimir, and is the IBF mandatory challenger after a win in August against Tony Thompson. The 32-year-old Pulev (18-0, 9 KO) might not be good enough to get the job done, but like Wladimir's most recent challenger Alexander Povetkin, it's more or less just time for him to go after it. He's not particularly young, he's likely as good as he's going to get, and this is basically what his pro career has been built around to this point.
There are other potential options, including Denis Boytsov, Chris Arreola, Odlanier Solis (or Carlos Takam), Malik Scott, Oleg Maskaev, Andriy Rudenko, I hope it's obvious I've let this become a joke sentence and so on, but Pulev is clearly the most attractive option from a (relatively) competitive standpoint and from, I guess, having "earned" the fight.