Both AC Milan and the Brazilian club on Thursday evening released statements confirming the 15-million euro transfer has been agreed pending a medical, and Pato will sign a four-year contract.

Instead of a signing-on fee, Pato has secured 40 percent of any future sale.

"I wish to salute, but above all to thank, everyone," wrote Pato in an open letter on the Milan website.

"From the President to the many people I worked with in these unforgettable years at Milan.

"I am going to Brazil, to Corinthians, so I'll have the opportunity to play consistently. It won't, however, be easy to forget Milan.

"I am and always will be very tied to this jersey, the club colors and all the Rossoneri fans. Above all at this moment my thoughts and my biggest thanks go to them."

Pato arrived at San Siro as a 17-year-old, but at the age of 23 his career has been blighted by a series of muscular injuries.