Wuertz had no decisions and a 6.68 earned run average in 39 appearances with the A's last season.
The 32-year-old right-hander went 8-4 with 10 saves and a 3.19 ERA in his previous two seasons in Oakland. He spent the first five seasons of his major league career (2004-2008) with the Chicago Cubs, and has posted a 21-11 record a 3.71 ERA in 426 career appearances.
In other team news, the A's claimed right-handed pitcher Evan Scribner and outfielder Cedric Hunter off waivers from the San Diego Padres.
Scribner began the season with Triple-A Tucson and made his major league debut on April 26, pitching two innings in an 8-2 loss to the Atlanta Braves.
He spent the majority of his season with Tucson, posting a 2-3 record with 10 saves and a 4.71 ERA .
Hunter made the Padres Opening Day roster and went 1-for-4 with a walk in six games before being returned to Tucson. He spent the remainder of the season in Triple-A and batted .255 with two home runs and 33 RBI in 81 games.