Usually, defensive midfielders are some of the easiest players to replace in soccer.  While the role has become increasingly defined in recent years, if a man deployed to bring energy in the middle of the pitch is struck down with injury, loses form or is sold, they don’t typically leave that difficult a void to fill.

But when it comes to Everton’s own midfield dynamo James McCarthy, it’s not an attitude the Toffees should be adopting. Even if, according to Graeme Bailey of, the former Wigan Athletic man is keen on leaving Goodison Park this summer.

The piece suggests that the Republic of Ireland international, a £13 million signing from the Latics in the summer of 2013, is unhappy on Merseyside because of the “respect”, or lack of, he is being shown at the club. Naturally, within minutes of the piece being posted, social media was ablaze with disgruntled Evertonians and if there is any credence to these stories, the Toffees must placate the situation swiftly, because McCarthy is the heartbeat of this team.

The path from Wigan to Everton is well trodden, with Roberto Martinez making the switch from one end of the East Lancashire Road to the other along with Joel Robles, Arouna Kone and Antolin Alcaraz; it’s a path Leighton Baines took earlier in his career too. But McCarthy has the potential to be the very best Latic-turned-Toffee.

Despite carrying injury problems throughout Everton’s desperate 2014-15 campaign, the midfielder’s admirable work-ethic was unrelenting at the core of the team. McCarthy is a purposeful, powerful runner, tracks opposition defenders with the rabid focus of a hunting dog and is ferocious in the tackle.

He’s about the only player in the Everton squad who can channel these desirable traits into top quality performances on the pitch. Muhammed Besic has a lot of similar qualities, but the Bosnia-Herzegovina international is erratic in possession and reckless in the challenge. At the moment, he’s not ready step in in the event of McCarthy’s departure.

Neither are Everton’s two other deep-lying midfield options, Gareth Barry and Darron Gibson. While both men can read the game well and ping passes about, the prospect of the ponderous pair together in the heart of the midfield would be a tantalising one for an intelligent opposition No. 10; the former, who was admittedly overplayed, looked very leggy last season, while the ex-Red Devil has been blighted by a horrendous run of injuries.

Given McCarthy’s clear significance, Everton could command a substantial fee for him and draft in a quality replacement. But to have a critical part of a bright young core—including John Stones, Ross Barkley and Romelu Lukaku—stripped away this summer would be a massive blow to the Toffees as they seek to banish memories of a ghastly 2014-15.

For the player, Everton remains an ideal environment to continue developing, especially if he wants to blossom from a destroyer to an elite, box-to-box midfielder.

Martinez thinks he’s capable of a more significant attacking output and there were encouraging signs towards the end of last season, coinciding with a decent spell of Everton form, no less, that the Glasgow-born star was beginning to relish an increased responsibility in the final third of the field.

That’s where he can take his game on next season. The talent is there for McCarthy to spring from deep positions, take shots and play incisive passes, but prior to last season’s late flourish, the fierce authority he displays in defence never materialised at the sharp end of the pitch; some all action displays in the run-in gave the 24-year-old some renewed attacking impetus, though.

With that potential for growth in mind, if McCarthy is willing to sign a new deal, as implied by Jones’ piece, this apparent standoff is a peculiar one. The player has done enough in his two seasons on Merseyside to warrant a salary to match the club’s top earners, even he does have three years still to go on the five-year contract he signed in 2013.

In addition, if Everton aren’t willing to shell out the money the midfielder wants, as is evident by the index of illustrious names linked with the player, including Manchester United, Manchester City, Arsenal and Tottenham Hotspur, someone else will.

Next season was always going to be a significant one for McCarthy in his overall development as a footballer. If the final stretch of games in 2014-15 was anything to go by, his influence on this Everton team is going to all-encompassing and Martinez is likely to demand the No. 16 adds more attacking sparkle to his vast defensive skill set.

But now, it seems as though this summer could be equally as important in determining where the player’s short-term future lies too. Everton, one way or another, must ensure it’s at Goodison Park, because although the bread-and-butter defensive midfielder mightn’t be too difficult to replace, McCarthy is on the cusp of being so much more than that.

Follow Matt on Twitter @MattJFootball