Ronaldo damaged a hamstring in Real's La Liga match at Almeria on November 23 and missed last week's Champions League win over Galatasaray and Saturday's La Liga success against Real Valladolid.
"I no longer have an injury," Ronaldo said at an awards ceremony in Madrid.
"I have been fine for a couple of days," added the 28-year-old, who has been on scintillating form this season.
"We preferred not to push things against Valladolid but I will be there for the next game for sure."
Ronaldo netted 14 goals in his last seven appearances for club and country before his injury and is one of the favourites to scoop the FIFA Ballon d'Or when the footballer of the year award is announced next month.
The former Manchester United man was the last player to win in 2008 before Barcelona's Argentine forward Lionel Messi took the next four.
"I am on good form," Ronaldo said. "It's possible that it is the best start to the season of my career but the past few years have also been very good."
Real's next match is a King's Cup last 32, first leg at third-tier Olimpic de Xativa on Saturday and they play at FC Copenhagen in the Champions League the following Tuesday.
The nine-times European champions are already through to the last 16 as Group B winners.
(Reporting by Iain Rogers; editing by Rex Gowar)
