Lukaku has always been better for the Serie A rather than the Premier League. We have proof for that considering his past statistics. 
Therefore Chelsea just signed him back for nothing. They were just fascinated with his performance at Inter and forgot about their past with him. It should be due to acting amateurish otherwise there is no way you do this.
Anyway he has returned to Italy but this time to Roma. It is a one-year loan deal though so I can't say good riddance for Chelsea. They will still have 2 more years with him in case he returns.
But let's say Roma didn't want to extend his loan and he didn't get any other reasonable offer in Europe then Chelsea can go for Saudi Arabia option for him.
I don't know why Chelsea insisted a lot to not let Lukaku go temporarily then just accept a deal with Roma although he was linked more with Juventus. It appears they are hopeless to see him go and they do not want to give him free money. Therefore Chelsea just signed him back for nothing. They were just fascinated with his performance at Inter and forgot about their past with him. It should be due to acting amateurish otherwise there is no way you do this.Anyway he has returned to Italy but this time to Roma. It is a one-year loan deal though so I can't say good riddance for Chelsea. They will still have 2 more years with him in case he returns.
But let's say Roma didn't want to extend his loan and he didn't get any other reasonable offer in Europe then Chelsea can go for Saudi Arabia option for him.
Hugo Lloris should follow but this time as a permanent move to Roma coming from Spurs since they do not want him anymore there.