The Portugal captain suffered a series of injury problems towards the end of last season and his coach is determined to ensure he is 100 percent fit before resuming full training.
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The Portugal international was plagued by injury problems toward the end of the 2013-14 campaign and was not 100 percent fit at the World Cup either.
He recently resumed training at Madrid's preseason tour to the USA, but Ancelotti has stressed that they will not rush Ronaldo back to action.
"We have to be careful with Ronaldo, and right now this calls for calm," Ancelotti was quoted as saying on the club's official website.
"Ronaldo did a double session today [Tuesday] and is working well on his own.
"We will see in the next few days if he can train with the side and play in the friendly against Manchester."
The Italian then went on to discuss Madrid's transfer plans this summer and hinted that the Champions League holders will have to sell first before signing anyone.
"We have to think about the players who are at Real Madrid at the moment," Ancelotti added.
"The market closes on Aug. 31 and a lot of things could still happen, but we have to think about what we have."
Madrid has already brought in Toni Kroos from Bayern Munich and James Rodriguez from Monaco, while the club is also expected to announce the signing of Levante goalkeeper Keylor Navas shortly.