The 35-year-old had surgery in September on a ruptured cruciate ligament and was ruled out for six months.
Sarri hopes to have Chiellini ready to return as soon as the experienced centre-back feels physically comfortable, with Juve entering a potentially decisive part of the season in which it plays five games in 16 days.
The Bianconeri head to Hellas Verona in Serie A on Sunday (AEDT) before two games next week, including a Coppa Italia clash with Milan on 14 February (AEDT). The first leg of the UEFA Champions League Round of 16 tie against Lyon is on 27 February (AEDT).
"He's proceeding as scheduled. Giorgio is alternating between individual and team training," Sarri said.
"The progress that he is making is very important. The most important thing right now is to listen to what he says to us. Clinically, he is totally healed. All that matters now is how he feels."
Sarri has no concerns about the fitness of Cristiano Ronaldo, who turned 35 this week and struggled in the first part of the season with a knee problem.
"Cristiano was in excellent condition in today's training and has been ever since he got over his knee trouble," he said.
Sarri plans to give more playing time to Adrien Rabiot, who has started four Serie A games in 2020 after starting just five times in the league before the turn of the year.
However, he insists Blaise Matuidi will have an important role to play during the remainder of the season.
"Rabiot is improving a lot and is in a very good moment, so I've picked him rather than other midfielders, but we can't forget who Matuidi is and what strengths he has," Sarri said.
"In the long run, Matuidi is one of those players who is always useful. This is just one period; there are lots of games to play.
"But now, I honestly think we have to give this guy [Rabiot] some consistency. He's finding confidence and form. I think he can improve further. I think it's important now to let him play four or five games to find consistency."