The News of the World says Grant's training methods have been described by one senior player as 'amateurish'.
"Under Mourinho, training was exciting and inspirational, it was different every day," said the player. "But since he left, training has been amateurish. In one session this week we were asked to get the ball and just dribble round a cone.
"Some of the players said they hadn't been asked to do that since they were 14 years old.
"There's no way Avram can last, he'll be gone by Christmas because the players just aren't having him at all."