The uncertainty over the Real Madrid player's ankle injury was settled when tests ruled him out of Saturday's game in Lisbon and the away leg in Zenica four days later, but it has overshadowed the run-up to an intriguing encounter.
Portugal's resurgent side are 10th in the world rankings, 32 spots above their opponents, but Bosnia are a free-scoring team close to their first major finals.
"In theory, we have an obligation to win. We are a serious candidate to be at the World Cup," Portugal coach Carlos Queiroz said.
"They have three players that can create goals on their own," Queiroz said.
Dzeko's club-mate Zvejzdan Misimovic is a classy number 10 and Zlatan Muslimovic is also a prolific scorer, while Lyon's Miralem Pjanic is deadly from free kicks.
Bosnia's defence conceded 13 goals in the qualifiers and will be relieved not to face Ronaldo, although Portugal are dangerous even without him.
Nani and Simao both played well and scored in Portugal's qualifying revival, while Liedson is a dangerous poacher.
Queiroz hoped playmaker Deco could replicate his recent form for Chelsea. The coach was also confident the Portuguese players' experience would be a key factor.
"We have to use our experience and maturity. This game may seem like it is the game of our lives. It would be important if our players found the tranquillity to face it as just another game in their careers," Queiroz said.
