Vincenzo Montella is reportedly ready to resign as Fiorentina manager if the Serie A club agree to sell Juan Cuadrado to Chelsea this month.
The Colombian has been heavily linked with a move to Stamford Bridge in recent weeks, with the Blues believed to be offering around £20.5m to seal a deal.
However, The Express claims that Montella has threatened to quit the Viola if Cuadrado is allowed to leave the Italian giants in the midst of their push to secure a Champions League place for next season.
Chelsea are believed to have turned to Shakhtar Donetsk's Douglas Costa as a possible alternative, but may face problems regarding valuation.
The Premier League side are said to have offered around £20m while the Ukrainian champions are thought to be holding out for £30m.