His agent has confirmed the Premiership champions have already made a bid for the Italy international.
Quagliarella’s agent Silvio Pagliari said: “One month ago, Manchester United made a £10million offer.
“We believe Fabio is worth between 15 to 20 million euros (£10-13million), hence if the English club’s offer still stands, he could probably go abroad.”
Quagliarella is co-owned by Sampdoria and Udinese.
