Boateng has confirmed his exit from Spanish La Liga giants FC Barcelona following his unsuccessful loan spell.
Boateng made a stunning move to Barca from Sassuolo in January, but he is on his way back to Mapei Stadium after just four appearances for the Blaugrana, who have chosen not to exercise their €8m option to buy.
“Today ends one of the most exciting experiences of my career,” the 32-year-old wrote on Instagram.
“I thank every person who made this possible. I thank my teammates who made me feel at home from day one, champions and great people.
“I thank all the management, available and always present. A special thought goes to all the fans: I will always carry you in my heart.
“I wanted to give something more, but I did my best in every minute of training and game that was given to me to honour this fantastic shirt!”
He made just three appearances for the Bluagrana during his loan stint.