Manchester United seldom lose members of staff they want to keep but, when one of their best coaches receives the offer of a first-team managerial role at another club, it's almost impossible to stop them leaving. Carlos Queiroz, for example, was hardly going to turn down Real Madrid in 2003.

The most recent departure, albeit in less exalted circumstances, was Warren Joyce, who left his long-term role as reserve/under-21/under 23 manager to take charge at Championship side Wigan Athletic in November.

The former Bolton Wanderers, Preston North End, Plymouth Argyle, Burnley and Hull City midfielder spent 12 years with United and on Sunday, two month after leaving, he will bring his struggling side to Old Trafford for an FA Cup fourth-round tie. Initially, Joyce was United's man at Belgian side Royal Antwerp, where he oversaw the development of on-loan young players. He returned United to manage the club's reserves in 2008, co-managing the side with Ole Gunnar Solskjaer, who later departed to manage Norwegian club Molde.

"Warren was absolutely brilliant in the very difficult role of reserve-team coach," says former United defender Gary Neville. "That reserve role is sandwiched between the first and youth team, both of which have longstanding formats: the Premier League and the FA Youth Cup. The reserve league has shifted several times -- it's now the Under-23 league -- and that doesn't make it easier for the manager. Nor does first-team managers saying they need two reserve players at the last minute for a training session or saying that a certain player has to play 60 minutes of a reserve game; Warren then has to drop a reserve player, who he's been preparing for a match.

"Warren was excellent at man-managing individuals who were hovering and drifting between the age of 19 and 21," Neville continues. "They'd be going out on loan, they'd have had a taste of the first team and the buzz of playing for the reserves will have worn off because they want to be playing in front of big crowds for a first team; they want a new contract. It can be an uncertain time for a player but he motivated them mentally and physically.

"He maximised the players' talents, he'd push them like crazy; he'd do extra gym work and join in with the players as if to say 'we're in this together'. He had a very good way of dealing with footballers, who he knew were not going to make it at United. He had a personal loyalty to them; he'd help them get a club away from United, but he also knew that they needed a higher level of toughness, that the player who'd come to him as a boy straight from school at 16 needed to be transitioned into a man by the time Warren had finished with them."

Joyce was integral to the development of current United players like Paul Pogba and Jesse Lingard, as well as many who left United and enjoyed top-flight careers elsewhere, including Danny Drinkwater, James Chester, Fraizer Campbell, Ryan Shawcross and Danny Simpson.

Warren Joyce spent more than a decade at Manchester United. On Sunday he faces them as Wigan manager. Getty

"I still get texts from [Joyce]," says Michele Fornesier, now a Serie A defender at Pescara. "He, Jim Ryan and Paul McGuinness were amazing coaches and helped me be the best that I could be at that age. Warren was dogged in his determination to create professional careers for players that just fell short of the required standard to be a Manchester United player. He paid as much attention to those lads as he would the star kid, who had a glorious future ahead of him. He had no favourites, he treated all players the same, even the first teamers who played for the reserves."

Along the way, Joyce's teams won reserve league titles and his judgement was completely trusted by Sir Alex Ferguson and others.

"Warren had great faith in the underdog," says Neville. "Things had not gone well for Ritchie De Laet in Stoke's reserve team, yet Warren brought him to Old Trafford where he played some Premier League games for Manchester United. Players trusted his judgement, they enjoyed his training sessions and responded to his down-to-earth nature; there's an earthiness about him."

As well as his time at Antwerp, Joyce was player-manager at Hull from 1998-2000, but he's now in his first proper job as a boss, with all the resultant pressures. Like others who have left Old Trafford, he'll have had a significant jump in wages, though probably not up to ten times his United salary, as it was for Queiroz, Brian Kidd when he went to Blackburn in 1998 and Rene Muelensteen, who joined Brondy in 2006.

But with the extra money come heavier burdens. Some of those who went before Joyce were more successful than others in dealing with the reality of not only coaching, but the media, expectant fans and internal club politics.

At Wigan, Joyce is working with Nick Powell, who was one of his charges at United. Meanwhile, former United Under-18 coach Paul McGuinness has been helping with some training sessions at the 2013 FA Cup winners.

Wigan hope Joyce's excellent reputation of developing players will pay off, but it's been an early baptism of fire; his side sit 21st in a 24-team league and have won only three of his 12 league games in charge, including the last two. Playing at Old Trafford on Sunday will turn up the heat still further.