The 33-year-old outfielder hit .224 with one home run and 18 RBI, 10 doubles and four triples in 104 games with the Giants last season.
That was down significantly from his 2015 statistics, when he hit .291.with five homers in 115 games.
Blanco began his major league career with Atlanta in 2008. He was traded to Kansas City during the 2010 season. Blanco spent the last five years with San Francisco.
In eight major league seasons, Blanco hit .258.