The 20-year-old winger has been attracting attention from RB Leipzig, where he impressed on loan during the second half of last season.
Lookman was unused substitute in Saturday's win over Southampton, but Silva insists he remains an important player for the club.
"He is our player. You know what my technical opinion of the player is and the player knows. For me it is not an issue," said Silva.
"I understand some clubs are interested in him but at the end I told you last week, I told you two weeks ago, my opinion he is the present and the future of the club and we have to try to convince him to go in this way as well."