The 32-year-old hit .258 with six homers and 20 extra-base hits for the Bisons and Fisher Cats in 2013. He was originally selected in the 14th round of the 2003 First-Year Player Draft by the White Sox.
Nanita will have a chance to compete for a backup role in Toronto, but in all likelihood, he will start the season in Triple-A. He'll likely play alongside Kevin Pillar while others, such as Kenny Wilson, also could be in line for a promotion to Buffalo.
Gregor Chisholm is a reporter for MLB.com. Read his blog, North of the Border, and follow him on Twitter @gregorMLB. This story was not subject to the approval of Major League Baseball or its clubs.