The midfielder, according to the Scottish Sun, is the subject of interest from Watford.
The Hornets finished second in the English Championship and will return to the Premier League.
Ferguson is viewed as a key target with Rangers also understood to maintain an interest in the 21-year-old.
“Lewis has played in cup finals and he’s going to be an international player.
“I don’t need to convince Lewis to stay — he loves it at the club.
“If someone comes in for him, they are going to need a lot of money to get him away from here.”
Ferguson has been linked with Rangers on numerous occasions with both his dad, Derek, and uncle, Barry, playing for the Ibrox club.
He is not the only player interesting English clubs with Sunderland reportedly tracking Ross McCrorie.
According to the Daily Record, the Black Cats are eyeing an £800,000 move for the versatile star.
Capable of playing in defence and midfield, McCrorie only joined the Dons permanently earlier this season.
Sunderland are currently in the play-offs as they look to return to the Championship after years of under performance.
Like Ferguson, McCrorie is contracted until 2024.
It is set to be a busy summer at Pittodrie with arrivals and departures as Stephen Glass revamps the squad.
Jay Emmanuel-Thomas could arrive on a free deal when his Livingston contract expires.