Juventus visit fifth-placed Atalanta before hosting Atletico Madrid in the Champions League next week.
Maurizio Sarri’s side are just one point ahead of Antonio Conte’s Inter Milan after 12 matches, with Lazio and Cagliari eight points adrift of the leaders in joint third.
Atalanta have gone three league games without a win and will be eager to get back into the Champions League berths, as they sit two points off fourth place, before next week’s trip to Shakhtar Donetsk.
Atalanta’s fortunes have slipped following the thigh injury suffered to Colombian star Duvan Zapata, who scored six goals in six Serie A matches before being sidelined for their last five league games.
As Atalanta sweat on Zapata’s return, Juventus will be without full-back Alex Sandro, who picked up a thigh problem playing for Brazil, with Blaise Matuidi recovering from a rib injury.
Ronaldo had said he was not be at his best physical form, with Sarri saying the Portuguese star has a “little knee problem”.
But the 34-year-old wants to make amends after storming off when he was substituted in Juventus’s last game against AC Milan.
“In the last three weeks, I have played at a slightly reduced capacity,” Ronaldo conceded after his goal spree for Portugal.
“I don’t like to be replaced, no one does,” added Ronaldo. “I tried to help Juve even when injured.”
Full-back Danilo, who scored his first goal for Brazil during the international break, warned: “The games after the international break are never easy, let alone against Atalanta, a team who are doing well.
“We can’t make mistakes or underestimate them.”
Inter will be looking to make it a perfect seven league games on the road this season as they travel to Torino, before their European trip to Slavia Prague.
Conte’s side face a tough task against the Andrea Belotti-powered Torino, who ended their six-match winless run against Brescia last time out, and are in 11th position.
Serie A runners-up Napoli are in crisis, having slipped to seventh, and desperately need a result at 14th-placed AC Milan, who are themselves floundering.
Cagliari and Lazio will look to continue their strong form at lowly Lecce and Sassuolo respectively.
Roma have a chance to move into the Champions League places as the look to bounce back from last week’s defeat to Parma at home against tailenders Brescia.
One to watch:
Carlo Ancelotti’s Serie A runners-up last season head for AC Milan amid reports he has two games left to save his job.
Napoli have gone four games without a win in Serie A to sit seventh.
The southerners have 19 points — 13 behind leaders Juventus — their worst tally after 12 games since the 2011-2012 season when they finished fifth.
After being held 1-1 by Salzburg in the Champions League, they travel to Liverpool next week in a key game for the former Chelsea, AC Milan and Real Madrid boss.
100 – Torino captain Andrea Belotti’s Serie A goals
29 – Juventus’s unbeaten run against Atalanta — 23W, 6D
13 – Points between Juventus and last season’s runners-up Napoli
6 – Inter have won six in six on the road so far this league season.
5 – Years since AC Milan last beat Napoli
Saturday (all times GMT)
Atalanta v Juventus (1400GMT), AC Milan v Napoli (1700), Torino v Inter Milan (1945)
Bologna v Parma (1130GMT), Verona v Fioretina, AS Roma v Brescia, Sassuolo v Lazio (1400), Sampdoria v Udinese (1700), Lecce v Cagliari (1945)