Aguero, 33, is set to retire due to his recent heart problems, with an official announcement imminent, according to Spanish reports.
He's only played five games for his new club having sealed a move in the summer following the expiration of his Manchester City contract.
With Aguero preparing to walk away from football as a result of his crushing diagnosis, Barca are on the search for a replacement striker ahead of the transfer window reopening in January.
They are ready to offer Man United around £5 million to lure him away from England.
Cavani is in his second year at Old Trafford and is a free agent at the end of the season.
He's played second fiddle to Cristiano Ronaldo following his return to the club.
The former Paris Saint-Germain man could be swayed in leaving Man United for Barca, who are willing to give him regular playing time.
Barca, though, face stiff competition from Inter Milan who are also believed to be keen on snapping up the 34-year-old.
The Uruguayan has only played eight games in all competitions this season - including five Premier League appearances.
He has one goal to his name this campaign having bagged an impressive 17 goals in all competitions last term.
Featured Image Credit: PA
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