United have embarked on the Louis van Gaal era at Old Trafford, and the Red Devils have already landed two new signings in the form of Southampton left back Luke Shaw and Athletic Bilbao midfielder Ander Herrera, but Dutchman van Gaal still needs to add more new faces.
Fiorentina's Juan Cuadrado remains a top target, but United's focus appears to be firmly placed on Juventus midfielder Arturo Vidal. The Chilean international, 27, is one of the top central midfielders in Europe, and would cost a reported £40m to prise away from the reigning Serie A champions.
That huge asking price means that a deal is becoming increasingly difficult and ultimately unlikely. With that in mind, United have to start identifying alternatives, and one of those is believed to be Barcelona's Alex Song. The former Arsenal man is surplus to requirement at the Camp Nou after the arrival of Ivan Rakitic, but the Catalan giants have so far struggled to find a buyer for the Cameroon international.
That has led to speculation that United will move for Song if their bid for Vidal collapses - but that would a bad idea for the Red Devils.
Song, who turns 27 in September, hasn't been on the top of his game for some time now. It's true that United need someone in the mould of Nigel de Jong - who featured so prominently for van Gaal at the World Cup - to do the dirty work alongside Herrera, but Song takes it too far sometimes; as we saw when he petulantly elbowed Mario Mandzukic in Brazil.
That kind of attitude is what has seen him slip down the Barcelona pecking order, and why few teams have expressed an interest in him. It seems like Song's best days are behind him already, and United should instead be looking to sign someone with a bright future ahead of them - such as Sporting Lisbon's William Carvalho.
Either that, or United look for a box-to-box player like Vidal. Again, Song doesn't possess the technical ability of the Chilean, and is nowhere near the goalscoring threat that Vidal is. He may well be a whole lot cheaper than the Juve star, but the fact is that he just doesn't offer enough for United to justify signing him.