The 16-year-old was handed his Black Cats' debut by former manager Tony Mowbray at the tender age of 15 in December 2022, since making a further 10 appearances for the North-East club.
Finding the net in an EFL Cup fixture against Crewe Alexandra in August, Rigg became the youngest-ever goalscorer for Sunderland at just 16 years and 51 days.
The midfielder has been a regular in England's youth setup at various levels, now representing the Three Lions' Under-18s side, earning three caps since September.
According to the Sunderland Echo, Liverpool are keen on recruiting Rigg in the future, with a number of other high-profile clubs interested in his services.
Jurgen Klopp's Reds will reportedly face competition from Premier League rivals Manchester City, Manchester United and Chelsea for the Sunderland man.
It is also believed that perennial Bundesliga winners Bayern Munich are monitoring the progress of Rigg, meaning that he could join fellow Englishmen Harry Kane and Eric Dier in Bavaria.
Despite interest from a host of elite clubs, Rigg is said to be happy at the Stadium of Light and is targeting regular first-team football for Michael Beale's men instead of a transfer away.
Rigg has featured in seven Championship matches in the 2023-24 term but is yet to start a match in the league, with his only starting berth arriving in the EFL Cup.
On the topic of the second tier, it is understood that Mowbray is keen to bring the 16-year-old to Birmingham City, who now possess ambitions of promotion to the Premier League under their American ownership.
Due to Rigg being under the age of 17, heRead on sportsmole.co.uk