The Rossoneri chief has expressed his admiration for the Argentina international but recognised that he is powerless to sign the 24-year-old superstar
Speaking ahead of the Rossoneri's Champions League clash against the Spanish champions, Galliani confessed that he is an admirer of Messi, but noted that the Argentine seems determined to see out his career at Camp Nou.
"I would give everything to sign Messi, but it is impossible," he told Mundo Deportivo. "He is a symbol of Barca and after speaking with him, he told me he is very happy at the club.
"I think he will retire at Barca."
The Milan chief then commented on the Catalan club's interest in Thiago Silva, stressing that his side are keen to hold on to the Brazilian centre-back.
"I hope I will come to Barcelona this summer, but not to negotiate over Thiago Silva," Galliani noted.
"Milan will not let this player leave."
Seydou Keita has been strongly linked with a new challenge in the summer after becoming a bit-part player at Camp Nou, and Galliani did not rule out a move for the Mali international.
"He could be a good addition to our team, but right now we are not thinking about signing anyone from Barca," he explained.
"We are only focused on the competitions we are involved in."
Milan are set to lock horns with Barca in the second leg of their quarter-final on Tuesday at Camp Nou, with the tie delicately poised at 0-0.