An injury-plagued 2010 meant limited appearances in Wigan's junior teams, however, he did play in the Under-20 Cup Final win over St Helens.
[citation needed] On his return to Wigan, Mellor was sent on loan to Widnes along with Dom Crosby and Logan Tomkins.
After the departure of captain Kevin Brown to the Warrington Wolves at the end of 2016, Mellor was handed co-captaincy alongside Chris Houston, and has been given the number 6 jersey.
[5] On 3 October 2022, Mellor played for Leigh in their Million Pound Game victory over Batley which saw the club promoted back to the Super League.
[7] Mellor played 23 games for Leigh in the 2023 Super League season as the club finished fifth on the table and qualified for the playoffs.