Anceloti said either Angel Di Maria or Jese would take Ronaldo's place against the Turkish club.
"I'll decide which one tomorrow," Ancelotti said from Madrid's training ground.
He said center back Raphael Varane would also likely be unavailable until the next Champions League game in Denmark as he rests a sore right knee.
"His knee needs some time off to rest and recover," the coach said. "For 10 or 12 days he won't play and we hope his knee doesn't swell during this time. He won't have surgery."
Madrid is already without injured midfielder Sami Khedira and defender Fabio Coentrao, while midfielder Luca Modric is suspended for the game. But midfielder Xabi Alonso and defender Marcelo were included in the 19-man squad despite injury concerns.
Madrid can secure a place in the next Champions League round with a draw on Wednesday.