The A's made the announcement Friday, saying Punto was released to clear room on the 40-man roster. A day earlier, Oakland acquired right-handers Jesse Hahn and R.J. Alvarez along with an international signing bonus slot from San Diego for catcher Derek Norris.
Punto, a 14-year veteran, was due to make $2.75 million after his contract option for the 2015 season vested.
Punto was limited by a hamstring injury during the 2014 season, when he batted .207 with two home runs and 14 RBIs with seven doubles and two triples in 73 games in his first season with the A's.
The San Francisco Chronicle first reported Punto's release.