The 24-year old was born in Sarajevo but fled the war-torn city during the 1992-95 conflict in Bosnia with his mother and sister. He won the European under-21 championship with Netherlands in 2006 and 2007 after adopting Dutch nationality.
Medunjanin's father was unable to leave Bosnia with his family and was later killed in the fighting.
"I'm not sure if I will be able to play any part either in Lisbon or the return leg in Zenica on Wednesday but it is a very special feeling to be a part of this squad," Medunjanin told the online edition of the daily Oslobodjenje on Friday.
"This is probably one of the most important ties Bosnia have ever played and although Portugal are a force to be reckoned with, they are far from invincible. I saw them several times in qualifying and they have not impressed me once."
Earlier this month, the Bosnian Football Association appealed to the world governing body for a summary procedure that would allow Medunjanin to change soccer nationality.
GOALKEEPING DILEMMA
Bosnia coach Miroslav Blazevic also faces a goalkeeping dilemma, mounting injuries and a possible suspension crisis as nine of his players could miss the return leg if booked.
Having said earlier this week he would drop first-choice goalkeeper Kenan Hasagic to the bench because of poor form, Blazevic now appears to be in two minds over whether to replace him with either Nemanja Supic or Asmir Begovic.
"Things have changed a great deal because Hasagic has somehow rediscovered his form and lost the pain in his body after I told him he was out of the starting lineup," Blazevic told Oslobodjenje.
"We have to get this one right and I am in a tight spot here because it's my decision and my decision only."
Midfielder Semir Stilic and striker Ermin Zec have been ruled out of both legs with thigh injuries but Blazevic remained confident Bosnia could spring an upset.
"I will field the best available lineup in Lisbon and, although Portugal are a mighty team, we have enough players capable of causing them problems."
