Juan Cuadrado's future at Fiorentina is set to become clearer when he holds talks with club president Andrea Della Valle on Friday.
Cuadrado returned to preseason training with the Viola on Wednesday -- but Gazzetta dello Sport reported that he later drove angrily away from the training ground.
The 26-year-old is under contract at Fiorentina, whom he joined from Udinese last summer, until 2017.
He impressed at the World Cup in Brazil, scoring once and setting up four other goals as he played in all five of Colombia's matches.
United and Barca are both reported to be monitoring developments, although it is thought unlikely that either would be able to sign the player for less than 40 million euros.
Coach Vincenzo Montella sees Cuadrado, together with Giuseppe Rossi and Mario Gomez, as key to his attack-minded formation.