"We know Ronaldo is an important player, but the most important thing here is the group. It would have been important to have him, but we have top quality players who will do their best. Cristiano's absence cannot serve as an excuse," he said.
The world's most expensive player hurt his ankle in late September and aggravated the injury in Portugal's 3-0 win against Hungary 10 days later.
He has not played since and tests by national team doctors on Tuesday ruled him out of Portugal's games against Bosnia in Lisbon on Saturday and Zenica four days later.
Simao said he was confident the side would book a berth at the finals in South Africa next year by winning a tie he sees as the most important of their lives.
"The tie will be complicated. Bosnia has great technical quality, but we had time to prepare the game. We know what we have to do to win. It's the most important game in our careers. We will be at our best level," Simao told reporters.
"The perfect Saturday would be a win for Portugal without conceding goals," the winger added.
Portugal, 10th in the world rankings, are seen as favourites to beat the attack-minded Bosnia side, but their coach Carlos Queiroz said neither team was favourite.
"It will not be an easy game, but it won't be calm for Bosnia either. Both teams have possibilities, neither side is favourite. Details and concentration will make the difference," Queiroz said.
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