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.
1. 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
2. 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
3. Netting against Barnsley!
Roy Keane's in-form Sunderland recorded their ninth win in 11 Championship games. Substitute Daryl Murphy set-up midfielder Grant Leadbitter to fire them in front with a right-foot shot. And in the last minute David Connolly scored to the delight of the over 8,000 away fans at Oakwell.
Photo: Clive Brunskill
4. Grabbing the winner against Southampton with another stunner
Sunderland went top of the Championship table after coming from behind to see off play-off hopefuls Southampton after stunners from Carlos Edwards and Grant Leadbitter handed the Black Cats a come-from-behind win at St Mary's back in 2007. A crucial result as Sunderland eventually went on to win the Championship under Roy Keane.
Photo: Christopher Lee