A report in The Daily Express claims the Gunners are interested in re-signing Alex Song. However, Arsenal will be making a huge mistake if they bring the FC Barcelona flop back to the club.

Song left Arsenal last summer, after occupying the defensive midfield role for the previous three seasons. At least he did in name only. Truthfully Song was never a credible defensive midfielder.

He often left the Gunners back four exposed. The problem wasn't just his sluggish, languid approach to many games. It was the numerous ill-advised runs forward to support attacks that already featured enough forward players.

At times these ventures into advanced areas did yield positive results. The Cameroon midfielder steadily developed a niche as an advanced creator. The 2011/12 campaign was often defined by the supply from Song to the prolific Robin van Persie.

His precisely lofted chipped passes over the top for the Dutchman, produced winning goals against Everton and Liverpool. Yet for everything good he did going forward, Song neglected his primary function in the team.

Song had arguably the most important role in Arsenal's hybrid 4-3-3 formation. He was supposed to act as the anchor at the base of the midfield. His vital purpose was two-fold.

First the robust midfielder was supposed to allow Arsenal's more natural schemers the freedom to attack. Second and perhaps most important of all, Song was supposed to act as a protector for Arsenal's centre-backs.

In manager Arsene Wenger's style of football, the full-backs are vital and regular attacking outlets. That leaves the central defenders constantly at risk of being exposed to counter-attacks. It is the job of the defensive midfielder to drop and cover for the advancing full-backs and break up counters.

Yet Song was hardly ever positioned to carry out those crucial tasks. His main issue appeared to be a lack of consistent effort. Shortly after his transfer, rumours emerged that Song's exit had been sparked by his complacent attitude and laziness in training.

Those rumours were lent some credibility by a series of careless performances on the pitch. Few can doubt that Song has the ability, but he rarely shows it. In particular, he often fails to produce in a games against so-called "lesser teams."

This cavalier approach perhaps explains why Song has failed so spectacularly to make the grade at Barcelona. In a larger, more talented squad, Song has been challenged to deliver maximum effort to warrant regular participation. It's no surprise he hasn't managed either.

However, despite all this, some Arsenal fans may welcome suggestions Song could return. Wenger certainly struggled to replace him, testing even more ill-suited players at Song's old position.

These experiments have included playing Mike Arteta in a holding role and foolishly relying on the ultra-brittle Abou Diaby. Song's versatility as a midfielder and centre-back could therefore be a major boost.

Yet the reality is that while Song can play both positions, he is not great at either one. He is the ultimate jack of many trades, but master of none. Wenger may have spotted Song's talent when he snared him from Bastia in 2005. However, what ability there was, the Arsenal boss has already developed and honed.

Arsenal's need at both defensive midfielder and centre-back is too great to simply settle for a mediocre, albeit familiar option. Just as important, at a time when Arsenal need fully committed players to drag them out of the mire, bringing back someone as casual as Song would be a huge mistake.