After an impressive season on loan with the club in 2012/13, scoring eight goals, Inman has agreed terms on a three-year deal for an undisclosed fee after rejecting a contract extension offer from the Premier League side.
But Davis confirmed the 21-year-old is short of full match fitness and plans on playing him in some Under-21 matches to speed up that process.
Inman will travel with the squad to London ahead of their match with League One leaders Leyton Orient on Saturday.
Davis told the club's official website: "Brad is fit and raring to go but he is short of match fitness. He needs some game time and the proof will be in the pudding with that. When we get him back playing in matches then we will know a bit more.
"We will integrate him back in and the Under-21 games have started again, so that will also give us a chance to assess how he is. We will take him to London as part of the squad again and we'll see if he is in our plans or not."