The 31-year-old was forced off during the entertaining 2-2 draw at Stamford Bridge and now faces an extended period out of the team.
Asked about Kante’s injury, Tuchel told reporters: “[It’s] quite serious. We’re talking about weeks. Not good news.
“We are disappointed and sad because N’Golo is super important and super fit. He will be out for weeks.
"Same with Armando. He will be out for days. He cannot come with us to Leeds.
"Mateo Kovacic as well, still out with knee problems. Christian Pulisic had problems but trained today. Let’s see.”
Chelsea announced earlier on Friday the signing of Cesare Casadei in a £12.6million deal from Inter Milan.
The young midfielder has been compared by some to Frank Lampard for his goalscoring ability.
However, Tuchel moved to play down any immediate expectations and explained that Casadei is a signing for the future.
“I’m not so sure if we do him a big favour if we join in this discussion (about his similarities to Lampard). I met him yesterday here in the building,” Tuchel added.
“We will give him time now to learn the language, to learn what Chelsea is all about, to understand the culture, how we live here and train here on a daily basis.
“Once he is settled in we will give him the opportunity to train with us and show his qualities. Then we will assess him and I have a clearer picture of him. Then, we will see.”