But Lukaku would have to agree. I don't know any details about his contract, but Chelsea want to have a player in their team that is not willing to play the best he can and Lukuku can be a moody guy, which also reflects upon his efforts in a game.
Lukaku still really wants to be at Inter. And even he also rejected the very high salary offer from the Arab League in favor of Lukaku. Yes, it's true, Chelsea doesn't seem to suit him very well and indeed, the competence of the players is not only in their skills but also in their mood and attitude. Apart from that, it seems that Lukaku is quite suitable for Inter's style of play.
He had a good season at Inter Milan and he could have a good performance there, especially in the last weeks when Inte Milan was playing in the champions league Lukaku also helped them in Serie A however he is under contract with Chelsea and Inter Milan should have some negotiations with Chelsea about this player for the next season.