Angel di Maria
Angel di Maria has struggled to adapt to life in the Premier League since joining Manchester United from Real MadridGetty

Rio Ferdinand believes Manchester United are probably making the correct decision to sell Angel di Maria, with the midfielder set for an imminent switch to Paris Saint-Germain less than 12 months after arriving in English football.

Di Maria, 27, became the most expensive player in British history when he moved to Old Trafford for a £59.7m ($93.2m) fee just three months after helping Real Madrid to Champions League success in May 2014, yet struggled to showcase his quality on a consistent basis under manager Louis van Gaal amid certain distracting off-field issues such as the attempted robbery of his home.

The Argentine international never quite shone in a variety of different formations and systems deployed by Van Gaal that included him at the top of a midfield diamond and out on the flanks, with such a high-profile struggle leading former suitors PSG to swiftly rekindle their interest.

As reported by The Guardian, the French champions have now agreed a £44.3m fee for the 27-year-old's signature and are expected to announce the deal upon the completion of a delayed medical in Qatar on 4 August.

Di Maria a 'failure' at United

According to Ferdinand, Di Maria is likely to regret his premature departure from United and while he wanted him to stay from a fan's perspective, he claims he understood why the sale was being sanctioned if indeed Van Gaal has already deemed him surplus to requirements.

"He will now always have on his CV that he was a failure at Man United," the 36-year-old, who joined the club from rivals Leeds in 2002 and spent 12 years there before ending his playing career at Queens Park Rangers, was quoted as saying by ESPN.

"As a professional, I wouldn't want something like that on my record. If I could rectify it by staying and trying to prove myself, I would have done that. As a fan, I would have liked for him to stay there and prove he can perform for Man United. That is what we all wanted to see when the club paid so much for him last summer, but that isn't happening, it seems.

"I can understand why some fans are disappointed that he is leaving so soon, but this is a business. United may have looked at it this summer and Van Gaal has probably come to the conclusion that he doesn't fit into his system for whatever reason. At that point, you have to cash in."

More Manchester United departures

Di Maria is set to become the second player to leave United for France after Brazilian right-back Rafael joined Lyon on a four-year deal yesterday (3 August). Nani and Robin van Persie are among the other senior first-team players to have been moved on during the current transfer window, with both choosing to join Fenerbahce. Striker Angelo Henriquez also moved to Croatian outfit Dinamo Zagreb on a permanent deal after a successful loan spell.

With regards to incomings, Van Gaal has significantly strengthened his midfield by signing Morgan Schneiderlin in addition to World Cup winner Bastian Schweinsteiger from Bayern Munich and PSV Eindhoven's Memphis Depay.

Italian international full-back Matteo Darmian has also arrived from Torino, while goalkeeper Sergio Romero joins as a free agent amid ongoing uncertainty surrounding the futures of David de Gea and Victor Valdes.