The Giants released Jackson from his minor-league contract Aug. 23.
The 29-year-old utility infielder has now been cut loose by both organizations in the Bay Area this season, as Oakland previously released him in July. Jackson, who appeared in three games with the Athletics earlier this season as a COVID-19 replacement player, saw action exclusively at Triple-A Sacramento during his time in the Giants organization and batted .200 over 10 games.