Barcelona may have signed Alex Song from Arsenal this summer, but it has been revealed that the club had drawn up a list of four Gunners targets.

Barcelona-based publication El Mundo Deportivo reports that Abou Diaby was highly rated by the Catalan giants, while Jack Wilshere and Thomas Vermaelen were also under consideration. Eventually of course, Barca successfully lured Cameroon midfielder Song away from the Emirates.

According to the report, one factor counting in Song's favor was that his agent, Darren Dein, was familiar to Barcelona as he also represents another player who made the journey from North London to Catalonia-Cesc Fabregas.

Sporting director Andoni Zubizarreta claimed that Song was top of their list of targets. There were reports during the summer, however, of Barcelona potentially making a move for Vermaelen.

It is reported that Barcelona were initially looking for a central defender and made approaches for both Thiago Silva and Javi Martinez before being priced out of moves by Milan and Athletic Bilbao, respectively. When Malian midfielder Seydou Keita left the club, however, Barcelona focused on a player who could perform in both defense and midfield, which is where Song came into the reckoning.

The news is sure to concern Arsenal fans, who have become increasingly concerned by the propensity of their best players moving to rival clubs both in the Premier League and Europe.

Fabregas left for Barcelona last year in addition to the departure of Samir Nasri to Manchester City, while this summer Arsenal lost Song as well as Robin van Persie to Manchester United.

With Diaby being so highly-rated by Barcelona, there will doubtless be a fear that he could be next. The French midfielder has been blighted by injuries in recent seasons, but has made an impressive start to the campaign-excelling in Arsenal's win over Liverpool and then scoring the only goal on his return to the France team, against Finland.