12th October 2017, 21:52 | Leigh
The former Wigan Warriors and Salford Red Devils forward, who turned 34 in September, has spent the last three seasons with the Centurions and was under contract for 2018 but had the option to leave following their relegation to the Championship.
Leigh owner Derek Beaumont said: "I have become good friends with Gaz during his time at my club and it has been a pleasure to have him play in our colours.
"He has achieved so much in the game and I am grateful for his efforts, joining us in the Championship, sticking with it and eventually seeing us make it into Super League.
"He started the campaign in fantastic form until picking up an injury and ultimately that played its part in the way our season ended. Gaz deserves to end his time playing in the Super League after the career he has had and I wish him well in that campaign, as he still has a lot to offer in his no-nonsense game."
Hock, who has made a total of 297 appearances in his career including 17 on the international stage, said: "I have loved every minute of my time at Leigh. It is right up there with Wigan as the best clubs I have played for."