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.
9. Playing despite bereavement
The day before Sunderland's League One play-off semi-final second leg against Portsmouth, Leadbitter's mother sadly passed away. But Leadbitter played through the heartbreak of losing his mum to help Sunderland reach Wembley. A moment Wearside will surely never forget. Photo: Jordan Mansfield
10. Becoming club captain
Grant Leadbitter played out a boyhood dream as he was named club captain back in 2020. Max Power was named as team captain, With Bailey Wright as vice-captain. An honour for the Wearside-born midfielder. Photo: FRANK REID
11. Stunning striker against Doncaster Rovers
Grant Leadbitter won the League One goal of the month award for his memorable and stunning strike against Doncaster Rovers earlier this season. Leadbitter won 62% of the public vote and his stunning long-range effort. Photo: FRANK REID 2019
12. Sending Sunderland through to a final
After a nervy game, Grant Leadbitter scored the winning penalty against Lincoln City at the Stadium of Light to send Sunderland to Wembley in the Papa John's Trophy final at Wembley. Photo: FRANK REID 2019