The 19-year-old Belgian failed to make a breakthrough into Chelsea's first team under Villas-Boas in the 2011-12 campaign after joining the Blues from Anderlecht last summer.
Lukaku could not impress Villas-Boas's replacement Roberto Di Matteo either and has been farmed out on a season-long loan to the Baggies.
"The decision that Lukaku departed was not mine so I've nothing to say about it," said Villas-Boas. "He is obviously a player with tremendous talent that competed last year against two of the world's best players.
"Lukaku had frustrations that you can understand. It's up to him to compete and, when you are up against Fernando Torres and Didier Drogba, the job is difficult.
"He's ready for the Premier League. It's just that he didn't have enough time on the pitch last year."
Lukaku scored on his Premier League debut for West Brom in their 3-0 victory over Liverpool last weekend.