The Hoops are preparing to take on Northern Irish side Linfield in their Champions League qualifier on Friday evening, but Ntcham has stayed behind in Glasgow to work on his fitness.
Despite the French midfielder's absence, Rodgers nonetheless expects him to play a vital role this season following his switch to Celtic Park from Manchester City on Wednesday.
The Northern Irishman told Celtic's official website: "To make progress over the next couple of seasons, particularly at the European level, it is important for us to have those physical attributes in there.
"Olivier is a player I have been looking at for near on eight months now, so I was aware of him in the second half of last season and before that. He's a player I always felt could work well for us. He has everything: he's 21 years of age, he's got a little bit of experience in playing senior football, but now he really needs that opportunity to go and flourish.
"Technically, he's very gifted and, tactically, he understands the game at a good level. He has many different technical qualities - he can pass, he can dribble and he can shoot. He's highly gifted. Physically he has everything - he is powerful, quick and good in the duel.
"Mentally, it's just a case of him taking the next steps in his career, coming to play at a huge club with big demands and opportunity to play in the Champions League. For us, it's a very big signing."