Monkhouse, born in Leeds, began his career as a trainee with Rotherham United and went on to score 9 goals in 128 League appearances for the Millers.
The 35-year-old joined Swindon Town in June 2006, but injury meant that he but only made 10 league appearances for the Robins and he spent time on loan at Hartlepool United before signing a permanent deal at the Victoria Ground in January 2007.
A member of the side that gained promotion to League One at the end of the 2006/07 campaign, he was also named in the PFA League Two team of the year that season.
Released by Hartlepool in the summer of 2014, he scored 44 goals in 290 League games for the club and appearances in other competitions took his total appearances to 322.
He joined Bristol Rovers and helped them to win promotion back to the Football League.
Indeed, Monkhouse was ever-present in Darrell Clarke's side, making forty-two appearances scoring 8 goals - including against the Mariners in the Promotion Final at Wembley.
However, instead of going up with Rovers, he remained in the National League, ironically with Grimsby, who he joined in June last year.
And he appeared thirty-eight times for the Mariners, scoring 6 goals, and made it a Wembley `double` in helping them to Promotion Final success.