Mourinho: Ronaldo should be fit for Lyon
The Portuguese international picked up the injury just over a week ago and was left out of the squad for Real's La Liga clash at home to struggling Hercules on Saturday.
"I think he'll play, but I don't like it when players aren't 100 percent," Mourinho told a news conference.
"If he had to play tomorrow he wouldn't be, but if he trains Saturday, Sunday, Monday and Tuesday I'm convinced he'll be able to play."
Real, who drew 1-1 in Lyon last month, will be seeking to qualify for the quarter-finals of the Champions League for the first time in seven years when Lyon visit on Wednesday.
The Portuguese coach also took the opportunity to have another dig at arch-rivals and La Liga leaders Barcelona, who top the standings with a seven-point advantage over Real with 11 games left to play.
He again suggested Barca received favourable treatment from Spanish football bosses in the scheduling of games.
"It isn't the same for everyone," Mourinho said.
"I'm not stupid and we all know that if the gap between the teams grows bigger the championship is lost.
"When one team plays in the Champions League on Tuesday and in the league on Sunday (Barca), and the other on Wednesday and then Saturday, they aren't giving Real Madrid the same chances to compete."
After facing Lyon, Real face a city derby against neighbours Atletico Madrid at the Calderon next Saturday.
Having hosted Arsenal at the Nou Camp on Tuesday, Barca travel to face Sevilla this Sunday.