The Colombian international has long been lauded as one of European football’s top midfield talents, and has been linked with a move to the Premier League on several occasions.
United, Chelsea and Spurs are thought to be the most interested of the English sides, but the trio may be set for disappointment with Barca also keen.
The Catalan club are far from short on central options, but manager Tata Martino is looking to add greater physicality to his side.
While the likes of Xavi, Andres Iniesta and Cesc Fabregas are all wonderfully creative, none of the three attack-minded midfielders are particularly imposing.
Guarin is known for his commanding style of play and is thought of as a player capable of driving his team forwards.
Martino is keen to add him to his ranks, and has personally asked Barca president Sandro Rossell to pursue a deal for the ex-Porto man.
Guarin is a favourite of Tottenham chief Andre Villas-Boas – who worked with him at the Estadio do Dragao – while both Chelsea and Manchester United are thought to see him as a perfect addition to their respective midfields.