"These words will live with me forever. From the bottom of my heart, I want to thank you, the dedicated fans of San Francisco and the fire in your hearts for Giants baseball. …
"It has been an experience that has shaped the lens that I will see life through for the rest of my time. I feel so very blessed to have been part of it all.
"Thank you San Francisco."
Zito inked a seven-year, $126 million deal with San Francisco before the 2007 season. The contract includes an $18 million club option for 2014, but the Giants are expected to buy it out for $7 million.
The 35-year-old mostly struggled in San Francisco -- going 63-80 with a 4.62 ERA in seven seasons -- but he was a part of two World Series-winning teams.
Zito was especially instrumental during the 2012 title run, going going 2-0 with a 1.69 ERA in three postseason starts -- including tossing 7 2/3 shutout innings in Game 5 of the National League Championship Series against the Cardinals.
Cash Kruth is a reporter for MLB.com. Follow him on Twitter at @cashkruth. This story was not subject to the approval of Major League Baseball or its clubs.