Uggla was released last Friday by the Braves after hitting just .162 and losing his starting job. The move was announced during Monday night's game against the Phillies.
The Giants haven't had much production from their second basemen this season. They're hoping a change in scenery helps Uggla.
The 34-year-old Uggla has 233 career homers and .244 average. He had five straight 30-homer seasons for the Marlins and Braves between 2007-11. He hit .196 with 43 homers and 143 RBIs in 1,101 at-bats since 2012.
Uggla will cost the Giants only $500,000. The Braves are responsible for the $18 million he's guaranteed over the rest of this season and next year.