The Real Madrid manager says his star, along with James Rodriguez, Toni Kroos and Angel di Maria, will be in contention to start the UEFA Super Cup on Aug. 14.
Los Blancos crashed out of the Guinness International Champions Cup on Saturday following a 3-1 defeat at the hands of Manchester United, and have scored just twice in three matches in the absence of Ronaldo and a host of stars given extended leave following their World Cup exploits.
The Portuguese superstar did make a surprise appearance as a substitute late in the second half, however, and Ancelotti believes another week training with the rest of the squad could see him back to peak fitness.
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"The team is not accustomed to playing without Cristiano Ronaldo, but it is normal that we are going through this," he told reporters after the match. "We can't be ready in the position we are in. We have players who just joined up a week ago and they aren't in the optimal condition, but it's something that is normal [for this time of year].
"Cristiano played 20 minutes which means his condition is improving. I think another week of training with the team and he will be ready for the first game of the season."
The forward is not the only one expected to make his return in the UEFA Super Cup on Aug. 14, as a lengthy list of World Cup participants, as well as new signings James Rodriguez and Toni Kroos, are expected to be available for selection.
"[James] joined us and began training yesterday. He will continue training and potentially play in the Super Cup," said Ancelotti. "[Kroos, James Rodriguez and Angel di Maria] are players who will return to the team and help improve the quality of the team — especially the two new ones."
Ancelotti said he was not happy with the loss to Louis van Gaal's side after a disappointing run of form in America but stressed it was a positive experience for a number of players.
"We are not happy with the loss, but I am sure we will play with another level of intensity and spirit in the Super Cup," he added. "It was a fantastic atmosphere and we are not used to playing in front of as many people as we did today. We tried to do our best for the fans. I think that the game in general was a good game.
"I think overall it was positive to get the players minutes and get them into the best physical condition, compared to training where you can't really tell. I think after a week of training it is good to have these types of matches so we can see where the players are."