The Spurs boss signed the 19-year-old for Chelsea during his short time at Stamford Bridge last season, but the Belgian striker never got a chance in the first team with Fernando Torres and Didier Drogba ahead of him in the pecking order.
Lukaku therefore joined West Brom at the beginning of this season in search of first team opportunities and has already got himself off the mark in the Baggies' 3-0 win over Liverpool on the opening day.
Albion visit White Hart Lane in the Premier League this weekend, and ahead of the match Villas-Boas told The Sun: “The decision that Lukaku departed [from Stamford Bridge] was not mine so I’ve nothing to say about it.
“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.”
The Spurs manager also had some kind words for his West Brom counterpart Steve Clarke, with whom he worked as part of Jose Mourinho's backroom staff at Chelsea.
He said: “It’s a long time since we worked together.
"Steve has taken his steps very wisely and I’m happy he has achieved his ambition of becoming a manager.
“I respect him a lot because he took those steps sensibly.
“He got the opportunity to be in the Premier League in a club as well organised as West Brom where he can build something extremely good.
“It’s a great chance for him so I’m happy. I congratulate him on getting the job.”