Date of birth
Experienced defender Mattock joined Pools on loan from Harrogate Town in October 2023.
The 33-year-old holds nearly 500 career appearances. He played for England at youth level and spent 12 seasons in the Championship with the likes of Leicester City, West Brom and Sheffield Wednesday.
Most notably, Mattock spent seven years of his career at Rotherham United, playing 225 games. He twice achieved promotion from League One, and also won the EFL Trophy at Wembley with the Millers.