Kante picked up the injury whilst on worldwide duty with France and is now undergoing weekly scans with Chelsea's medical team.
"For sure it will be very hard to play with Fabregas and Bakayoko for seven games in a row, and also we have to hope no injuries in these games".
"[From] the previous scan maybe [Kante will be out for] around 20, 25 days, but in this situation you must pay great attention". This is a big loss for us.
"We are going to do a scan next week to check Kante's situation, if he's improving". We must have patience with him and with this calf problem. We don't have another player with the same characteristics.
The 48-year-old told reporters: "We have to adapt a player in Luiz in midfield who is very important as a central defender".
Chelsea snapped Drinkwater up from Leicester City late in the summer transfer window and the midfielder has not yet had the chance to make his mark at Stamford Bridge. "When I made a decision to use him in the midfielder against Tottenham, it could be an option if I play with three midfielders".
Kyle Scott could also be called upon.
Morata had a scan last week, with Spain's medical staff claiming that he had suffered a grade two hamstring injury.
"Morata, I hope to have him back very soon".
Striker Alvaro Morata is also out of the trip to Selhurst Park after injuring a hamstring in the 1-0 home defeat by Manchester City at the end of September, but could be back in time to face Roma on Wednesday.