The Spanish playmaker was one of the club’s top targets last summer under the stewardship of David Moyes, but a lengthy pursuit of his signature ended in disappointment for the Red Devils.
However, Barca are now believed to be ready to get rid of their former trainee in the coming months as they set about a big period of change.
It is understood that offers of around £30m for the World Cup winner will be accepted, which is a figure that new United chief Louis van Gaal could to stretch to with reports indicating that he will be give around £200m to rebuild his first-team squad after their woeful 2014/15 campaign.
LVG is thought to be looking for a midfielder to become the focal point of his new team, and sees Fabregas as a player that could fit such a role.
Arsenal may also enter the running after inserting a buy-back clause into the deal that took the silky passer to the Nou Camp in 2011.