The centre-forward was signed by Porto last year from Atletico Madrid.
AVB said, "Samu has a great future and we want to preserve his talent.
"He's a super player, despite his young age, Samu is one of the best scorers in the world."
He also told AS: "We started this Samu project with Atlético. At first, 50/50. Now we've managed to buy all of his sporting rights.
"We want him to grow and become what we believe he will be. Joining Porto was the right step for him. The club is also a family, and he felt at home. We've already had contact with several clubs that wanted to take him."
Meawhile, AVB also discussed Porto signing former Celta Vigo superkid Gabri Veiga from Al-Ahly.
He added, "It was a wonderful signing for us. Under normal circumstances, Gabri Veiga would never have signed for Porto. We're talking, at that time, about one of the best talents of his generation in European football.
"He made the choice for Saudi Arabia at a young age and had a huge impact there, thanks to the trophies he won, the goals he scored, and the assists he made."