The Bernabeu coach says his side cannot afford to focus on their former striker alone, while Xabi Alonso has warned that his "frustrated" Los Blancos team-mate is ready to strike
Former Blancos forward Huntelaar will make his first appearance in this season's competition in the last-16 tie in Gelsenkirchen, while Ronaldo is also set to start after sitting out last weekend's Primera Division meeting with Elche as the final game of his three-match ban in La Liga.
Ancelotti has warned his side against focusing solely on nullifying Huntelaar, while Xabi Alonso has revealed that "frustrated" team-mate Ronaldo is raring to go for Los Blancos after his domestic ban.
"Ronaldo is especially motivated because he wants to play," he told reporters. "He wasn't happy with the sanction. He has trained very well during this time," Ancelotti told a press conference.
"Ronaldo's condition is optimal for tomorrow [Wednesday]. I don't think it's an individual duel between Ronaldo and Huntelaar. Huntelaar is a very good striker, a very good player across the attack, we have to be careful with him. But the match is between Madrid and Schalke.
"Schalke have a very well-organised defence, with very good young players like [Max] Meyer and [Julian] Draxler and others with experience like Huntelaar and [Kevin-Prince] Boateng.
"They play concrete football, not spectacular, but solid, with good organisation. They play very well together, they have quality.
"It will be a game with a lot of intensity. Schalke will try to do everything to win, that's clear. We will have to give everything."
Meanwhile Los Blancos midfielder Xabi Alonso says his team-mate Ronaldo has been left "frustrated" after a three-game ban from being sent off against Athletic Bilbao at the beginning of February, but is itching to return.
"He's been frustrated these last few days, but obviously for him not to play three games after Bilbao was unfair," Alonso told reporters.
"But it's water under the bridge. He looks the same as ever. It's an important competition and everyone is very focused."