The Bianconeri released their official squad list on Saturday:
Per Football Italia, Ronaldo's absence is not related to an injury, but he's being rested after heavy involvement to start the year.
Giorgio Chiellini was selected in the squad and could make his first appearance since tearing his ACL in training in August.
Ronaldo celebrated his 35th birthday on February 5, but manager Maurizio Sarri had opted against resting his star forward to that point. The Portuguese has scored in 11 straight matches in all competitions, including 10 straight in Serie A to set a new club record. He's just one goal shy of the overall record, held by Fabio Quagliarella and Gabriel Batistuta.
However, the veteran showed signs of fatigue in his most recent outing, the 1-1 draw against AC Milan in the Coppa Italia:
Brescia are winless so far in 2020. They also come into the match facing an injury crisis and will be without star prospect Sandro Tonali, goalkeeper Jesse Joronen and forward Ernesto Torregrossa.
Ronaldo's absence means Gonzalo Higuain is likely to start on Sunday.
Juventus next face SPAL—the only club below Brescia in Serie A—before the crucial UEFA Champions League clash with Lyon on February 26, giving Sarri the chance to rest some of his stars.
Leonardo Bonucci and Matthijs de Ligt have only had three games off between them so far in 2020, so Chiellini's return comes at the perfect time. He's been a full participant in training:
The 35-year-old is not expected to start on Sunday, but a substitute appearance in front of the home fans seems likely. Daniele Rugani could also feature in place of De Ligt or Bonucci.
Douglas Costa and Federico Bernardeschi will miss out through injury, so Juan Cuadrado could once again play in a more attacking role because of the team's lack of depth out wide. Under-23 prospect Wesley could be in line for his debut.