The German international is widely thought of as one of European football’s finest deep-lying playmakers, and was a key member of his club side’s journey to last season’s Champions League final.
United and Arsenal have been strongly linked with move for his signature in recent times, with rumours that he could allowed to leave the Westfalenstadion at the end of the season circulating due to his contract being set to expire in 2015.
Real Madrid are also keen, but now Barca have emerged as potential suitors.
The La Liga champions are believed to be looking at signing a new long-term midfield icon, with Xavi now entering the closing stages of his illustrious career.
Alex Song has been linked with a switch away from the Nou Camp in recent times, and the Cameroonian’s exit could free up space for Gundogan.
Reports have suggested that a deal is already in place for the 23-year-old to join Real with Nuri Sahin – on loan at Dortmund from Los Blancos – heading in the opposite direction, but these claims have been denied.