The Belgium international striker, 20, scored 17 goals for the Baggies during an impressive season-long loan with the club keen to get him back for a second year.
Lukaku himself was understood to be open to another loan stint as he believed his World Cup prospects would be enhanced by playing regular first-team football.
However, new Chelsea boss Jose Mourinho has ended speculation by telling Lukaku that he does want to utilise him regularly as a first-team player at Stamford Bridge.
The ex-Anderlecht striker said: "I'll play for Chelsea next season. I had a chat with Jose and he'll put me in his squad."