Casper then took backroom jobs at Bradford City and Grimsby Town, before joining the Premier League as a club support manager.
When still only 17, he signed professional terms in January 1993, making his United debut in the League Cup game against Port Vale at Old Trafford on 5 October 1994.
Casper was a product of the same United youth setup that sparked the highly successful careers of players such as David Beckham, Paul Scholes, Gary Neville, Phil Neville and Nicky Butt, who all spent a decade or more with the club, helping them win numerous trophies and also being regular members of the England national football team.
[3] Casper later had several spells on loan at AFC Bournemouth and Swindon Town during the 1990s, but was unable to claim a regular place in the first team at Old Trafford and he was sold to Division Two side Reading in November 1998 for £300,000.
More than four years later, he secured undisclosed compensation in an out-of-court settlement with Richard Carpenter, the Cardiff City player whose tackle had caused his career-ending injury.
Casper offered to resign in 2006 when Bury were thrown out of the FA Cup in the 2006–07 season for fielding an ineligible player, but this was rejected by the club's board.