The 34-year-old midfielder joined the Reds in January 2014 and went on to play 285 games, scoring 51 goals and winning four trophies.
He made his final appearance in our last fixture of the 2021/22 season, away to Crystal Palace on 22 May.
Mata had already won the Champions League, FA Cup and Europa League - all with Chelsea - when the Reds signed him on 26 January 2014.
In addition, the midfielder was a part of the Spain national side who won the World Cup in 2010 before triumphing in the European Championship in 2012.