According to Bild, Felix Sturm still has the urge to avenge a controversial loss in the US. It says that there is a possibility of facing Chavez in the US in August. If a unification fight can not be made, he needs to face his mandatory Gennady Golovkin next. source: http://www.bild.de/sport/mehr-sport/felix-sturm/sturm-auf-amerika-23639760.bild.html
He wants unification to avoid Golovkin but Zbik was his 5th voluntary in a row. Even if the unification doesnt happen im sure he'll be allowed to duck Golovkin as has been the case for the last 2 years fight after fight.
If Lee beats Chavez Jr. I doubt he will go to Germany to fight Sturm because of a possible "robbery". I think Lee/Chavez Jr will fight Martinez as the "contract" says in September. So Sturm will more than likely either fight GGG or duck him.