Leadbitter and Chris Maguire are among a group of seven senior players to have been released by Sunderland following last weekend’s defeat in the League One play-offs.
And supporters were quick to pay tribute to the Wearside-born academy graduate.
Indeed, many are keen to see the boyhood Sunderland fan remain at the club in some role moving forward.
The 35-year-old came through the ranks at the Stadium of Light and burst onto the first-team scene in 2006 under Mick McCarthy – delivering a number of priceless moments during the club’s time in the Premier League and Championship.
Leadbitter would later go on to represent Ipswich Town and Middlesbrough before joining the Black Cats in 2019.
But with his contract set to expire at the end of June, the midfielder will soon depart the club.
Here, we take a look at his best and most emotional moments in red and white.
. SOUTHAMPTON, UNITED KINGDOM - APRIL 09: Grant Leadbitter of Sunderland celebrates scoring their second goal during the Coca-Cola Championship match between Southampton and Sunderland at St Marys Stadium on April 9, 2007 in Southampton, England. (Photo by Christopher Lee/Getty Images)
SOUTHAMPTON, UNITED KINGDOM - APRIL 09: Grant Leadbitter of Sunderland celebrates scoring their second goal during the Coca-Cola Championship match between Southampton and Sunderland at St Marys Stadium on April 9, 2007 in Southampton, England. (Photo by Christopher Lee/Getty Images) Photo: Christopher Lee
. Making his debut!
Coming up through Sunderland's youth academy Leadbitter's first professional appearance for his hometown club came as a substitute in a League Cup defeat against Huddersfield Town in September 2003. It was bittersweet for the young Leadbitter as Third Division Huddersfield rubbed salt into Sunderland's wounds as they dumped the Division One side out of the Carling Cup. Photo: Warren Little
. Scoring a cracker against Burnley to give Sunderland hope
Under Roy Keane, Sunderland were 2-0 down against Burnley in 2006 before a cracker from Grant Leadbitter and a stoppage-time equaliser from David Connolly handed the Black Cats a vital point and some momentum in their race for promotion. Photo: Clive Brunskill
13. Winning at Wembley
Sunderland won at Wembley for the first time in almost 50 years as they beat Tranmere Rovers to claim their first EFL Trophy with Grant Leadbitter in the side. A Wearside-born academy graduate winning for Sunderland at Wembley. Poetic! Photo: Justin Setterfield