Alexandre Pato has taken "a brave step" in trying to resurrect his career in Europe, according to Chelsea boss Guus Hiddink.
The club announced on Friday evening that the Brazilian had completed his loan move to Stamford Bridge until the end of the season.
Pato spent five years at Milan before returning home in January 2013 to join Corinthians, who later loaned him to Sao Paulo.
The 26-year-old has not featured in a Brazil squad for more than two years, but Hiddink has denied the loan represents a gamble for Chelsea.
"Coming on loan makes it possible to have a good view on him, and on whether he is able to adapt to the high demands of the club and the league," the interim manager said. "It is a brave step. It's up to him."
Hiddink also confirmed the imminent arrival of United States defender Matt Miazga, who is close to joining from New York Red Bulls.
"We're not rushing, but he will be one of the squad members for the future," said the Dutchman, who also denied speculation Gary Cahill has become unsettled at the club.
Cahill has lost his regular starting place to Kurt Zouma in recent weeks but Hiddink, who spoke to the England centre-half this week, said: "There was no hint from his side 'can I leave the club?' Nothing.
"First he's very happy. He's of value and, as far as I'm concerned, I will have him in the upcoming months and I think the club will have him in the upcoming years."