The Switzerland international is due to see out the season in Germany after falling out of favour at Emirates Stadium.
He was allowed to move on in an effort to get games, with Arsenal favouring other options at centre-half.
The Gunners have not included an option to buy in the deal which took Djourou to Hannover, suggesting they still see a future for him in England, but the 26-year-old would be open to making a full-time switch if the opportunity arises.
"Arsenal did not want to include a buy option," said Djourou.
"But those things don't worry me right now. I have to perform first, to make sure Hannover want to buy me.
"As a team we have the quality to reach the Champions League.
"Everything has to work out great and we all have to stay fit. It is a high goal, but you need to have them in sport."