The Italy international signed for the Black Cats in summer 2013 but made just 32 Premier League appearances before being loaned out to Bologna at the start of last season.
But the 31-year-old went on to bag seven goals in 28 Serie A outings last term, demonstrating strong enough form to claim a starring role in Antonio Conte’s Euro 2016 squad.
Indeed, the attacking midfielder – who also played under Conte during two years at Juventus – has claimed one strike and one set-up at Euro 2016, playing a key role in wins over Belgium and Spain.
Giaccherini is almost certain to leave the Stadium of Light this summer and although a return to Serie A is the likeliest scenario, agent Furio Valcareggi has insisted he’d jump at the chance to work with Conte again at Chelsea next season.
As quoted by talkSPORT, he recently told Lady Radio; “There is Torino, Bologna and there is also a team abroad. I’d like to see him at Fiorentina, undoubtedly, but we have other situations at stake now.
“This is probably the high point of Giaccherini’s career. If Conte calls, we’ll fly to Chelsea.”