No deal has been agreed between the two clubs as yet and Villas-Boas stated that the 28-year-old is just one of the players under consideration.
"At the moment, he's just one of the players we are interested in," said Villas-Boas at a press conference in Hong Kong.
"It's not a lie to anybody that we've been looking for a striker to strengthen our squad and to have more strength in depth.
"Roberto is one of the players we have been following and his career speaks for itself. He's a great striker.
"But there isn't a deal being struck at the moment, it's just interest and conversations."