Ibaka has been nursing a left calf strain for the last 10 days. He participated in shootaround Sunday and declared himself able to play barring a setback. The Spurs lead the best-of-seven series 2-0.
"I'm trying to put my mind ready and if I'm going to feel better later, I'm going to go," Ibaka said earlier Sunday. "For now, we're going to see if I feel better, because normally when you do this kind of workout, sometimes you can have pain later.
"So I'm going to see how I feel later and then I'm going to decide."
Ibaka, who was initially expected to miss the remainder of the postseason because of the injury, which occurred against the Los Angeles Clippers on May 15, had his status unexpectedly upgraded to day to day on Friday.
"It is my decision. At this point, it is my decision more than Coach [Scott Brooks] or the doctor. So it is my decision," Ibaka said. "And like I said, I went through some offense and defense this morning with my teammates. I'm going to put some ice [on the calf] and see how I'm going to feel later."
Ibaka said Saturday that he would be willing to play through pain as long as he got clearance from the team's medical staff.
"It's 100 percent going to hurt," he said Saturday. "For sure if the doctor gives me the OK and I feel better tomorrow, I will be 100 percent with the pain for sure, but like I said, I'm going to do whatever it takes to help my team."
Ibaka, who said Saturday he had not practiced or even done any running, did end-to-end running on Sunday and a full shooting workout without any noticeable limp.
The Thunder lost the first two games of the series by an average of 26 points. The Spurs have shredded the Thunder's typically sound defense, scoring almost at will inside the paint in the best-of-seven series.
Ibaka, who has led the league in total blocks for four consecutive seasons, has been badly missed on the defensive interior.
"I would try to bring my teammates some defensive mentality," Ibaka said. "The most important thing against this team is defense. I'm sure you saw the last two games in San Antonio, so we really need defense tonight."