Manchester United are believed to be the frontrunners to sign Mats Hummels from Borussia Dortmund.
Reports suggest that the Red Devils have made an opening bid for the 26-year old centre-back who was one of Germany's best players at the 2014 World Cup in Brazil.
Arsenal are also keen on Hummels, who is being valued at around £35million, while Barcelona have previously been linked with the former Bayern Munich man.
United were unlikely to do any business in the January transfer window according to chief executive Ed Woodward and manager Louis van Gaal but it is being reported that the Dutchman is eager to strengthen his defence as the Old Trafford outfit, currently nine points behind leaders Chelsea and Manchester City, get set to launch into the second half of the Premier League season.
