The Portugal international scored a brace in Thursday's 3-2 win over Arsenal to make it 12 goals and 16 appearances for the 20-time English champions this season.
Ronaldo was substituted in the latter stages of the clash with the Gunners, though, and headed straight down the tunnel.
According to The Sun, the 36-year-old is struggling with a knee problem, which could have been caused when he performed his famous jump celebration after scoring his second of the match at Old Trafford.
The report claims that the issue has made the Portuguese a major doubt for Sunday's clash with Palace.
Rangnick lavished praise on Ronaldo while speaking during Friday's press conference, hailing the fitness of the former Sporting Lisbon youngster, who has six Premier League goals to his name this term. body check tags ::