The trio Douglas Costa, Blaise Matuidi and Mario Mandzukic are in a race against time to be fit for the game.
Juventus will be on against Jose Mourinho’s United on Wednesday night.
Juventus are in full control of Group H having won all their matches so far.
However, Juventus could be without three key players against United with Costa and Matuidi yet to train ahead of the clash, the club confirmed.
While Matuidi picked up a bruise on his right hip in the 3-1 win over Cagliari, Costa needed physiotherapy treatment on a thigh injury.
The French and Brazilian stars received treatment at Juventus’ training ground on Sunday and are doubts for the game against United.
Juventus boss Massimiliano Allegri also revealed midfielder Miralem Pjanic was feeling ‘tired’ in the game against Cagliari.
Striker Mandzukic is also a doubt after missing the win over Cagliari, but handed his side a boost by taking part in some training on Sunday.
