Aogo has fallen out of favour at Hamburg after infuriating club bosses by travelling to Mallorca to meet his agent after their 5-1 defeat by Hoffenheim earlier this month.
The Germany international was left out of the squad for Saturday's 1-0 loss at Hertha Berlin.
"He will be loaned out to us for one year," Heldt told reporters. "More transfers are possible."
Schalke could also be in the market for a striker after a long-term injury to Dutchman Klaas-Jan Huntelaar.
Fellow forward Adam Szalai could also be sidelined after injuring his hand in their 3-2 Champions League playoff win over Greece's PAOK on Tuesday.
The Hungarian hurt his hand in training and played with a bandage on Tuesday, scoring twice to steer Schalke, who have lost two of their opening three Bundesliga games, into the lucrative group stage with a 4-3 aggregate win.
Heldt, speaking on his way back from Greece, said Celtic were still interested in signing Schalke forward Teemu Pukki.