The Spanish attacker joined the Rossoneri on a one-year long, and although Barca has the possibility to block a move, he could stay at San Siro for longer.
The attacker joined the Rossoneri from Roma on a one-year loan deal in the summer transfer window after moving to the Giallorossi from Camp Nou a year before, but the Catalans have a contractual obligation to re-purchase the 22-year-old in the summer of 2013.
Nevertheless, Bojan could very well stay at Milan if the club opts to exercise its option to buy, and Barcelona decides not to block the move.
"We sold Bojan to Roma for 12 million euros, and are obliged to resign him for 13m euros in the summer of 2013. However, Roma then decided to send him on loan to Milan," Bartomeu stated at a press conference. "Milan really wanted an option to make Bojan's stay at the club permanent. So Milan have the option to buy him at the end of the season, when he is due to return to Barca.
"However, we can block Milan's option to sign him. I can not not disclose any more information on this, though, as Milan have asked for it to remain confidential."
Bojan made his official debut at the weekend in the 3-1 away win over Bologna.