The Wales international is a right-back who began his career across the Severn Bridge at Cardiff City, with whom he went on to make 48 appearances, scoring one goal.
Celtic took Swansea-born Matthews on a free transfer in 2011 where the Welshman won four consecutive Scottish Premier League titles, as well as Scottish Cup and Scottish League Cup medals in 2013 and 2015 respectively.
Matthews also bolstered his experience playing in the Champions League and Europa League with the Glasgow club.
A £2m switch to Sunderland took place in the summer but a couple of ankle injuries left him with only two first-team appearances to date.
The defender made his international debut in 2011 against Scotland and joined City on a season-long loan in the summer.