Asked if he considered Lukaku to have a future at Chelsea, Henrotay told The Newspaper: "Of course, Chelsea count on Lukaku.
"They will continue to follow him and evaluate after the season. There was so much interest. But West Brom is an ideal club at which to evolve.
"It is also important that Romelu can keep playing in the Premier League. Romelu has thanked Chelsea. The boy has two seasons of football played with Anderlecht. Another year on the bench was not an option. This is the best for all parties."
Lukaku has agreed a one year deal at the Hawthorns.