The Real Madrid forward will miss the last qualifier at home to rock bottom Luxembourg on Tuesday through suspension after receiving a yellow card for protesting in the dying minutes against Israel on Friday.
Russia, who are three points ahead of Portugal, travel to fourth-placed Azerbaijan on Tuesday.
"I can't talk about that (booking)," Ronaldo told reporters. "FIFA is always very attentive to those situations," he added, referring to soccer's ruling body.
"The playoff is the most important and I don't want to be out. I will be at those two matches."
Ronaldo said Portugal found it tough to penetrate Israel's wall of defence on Friday.
"We have to improve in many aspects," he said. "Israel had two buses behind the ball and when it's like that it's hard to score.
"We were apathetic in the second half, looked sleepy even, and things did not go well. We lacked a bit of maturity at times, maybe it was because we had a young team with a lot of changes."
Ricardo Costa put Portugal in front in the 26th minute but a late blunder by keeper Rui Patricio gifted Eden Ben Basat the equaliser.
Of all the teams Portugal could meet in the playoffs, Ronaldo said France were the side he feared the most.
"France are the strongest we may face," he explained. "They are the only ones I do not want to face."
Portugal have called up teenage Galatasaray forward Bruma and Inter Milan centre back Rolando to replace Ronaldo and Pepe against Luxembourg.