"If I am at the Asian Cup, I will miss at least a whole month" with Wolfsburg, Dejagah said in a statement on the club's website on Thursday. "I want to seek my chance here."
The striker of German club Wolfsburg, who plays as substitutes in most matches, added that he would stay with his team in the hope of making his breakthrough with the squad.
Former Germany Under-21 player Dejagah, who was born in the Iranian capital of Tehran but brought up in Germany, was allowed by FIFA to switch national sides.
FIFA's statutes allow players to change national teams before playing a senior international, and if they always were eligible to represent their second-choice country.
Meanwhile, Iran's manager Afshin Qotbi is in Germany to talk with the 24-year-old Dejagah to persuade him to play for the Iranian national soccer team in the upcoming tournament to be held in Qatar in January.
Iran should compete with North Korea, the United Arab Emirates, and defending champion Iraq for the 2011 Asian Cup.
Qotbi's men will begin their preparation for the Asian Cup on December 24 in Qatar's capital, Doha. The Iranian outfit faces Qatar and another opponent will be announced to meet Iran before the event.