Chelsea have the option to recall him during January.
Gera said: "I don't know what's gong on behind the scenes, but we're happy and I think he'll stay.
"I hope he'll stay. He scored a very important goal against Norwich but he's scored others as well.
"It was good for us to bring Lukaku here and it was a case of one chance, one goal.
"Upfront we have two very good players in Shane Long and Lukaku and if they get just one chance they have to score. That makes a difference."