Blind is a target for new United manager Louis van Gaal as he prepares to lose former club captain Patrice Evra.
The Dutchman's versatility means he can fill in at left-back without representing a long-term threat to £30 million signing Luke Shaw.
However, Sport says Barcelona are also interested in Blind after being frustrated in the pursuit of their top defensive transfer targets.
Like Van Gaal, Barca coach Luis Enrique admires Blind's versatility. The midfielder is now inside the final two years of his current deal.
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