Munson's deal doesn't include a Spring Training invitation to Major League camp. He will report with Minor League players on March 14.
Munson, 32, is a San Diego native who has a career .214 batting average over parts of nine Major League seasons with Detroit, Tampa Bay, Houston and Oakland.
Munson, who was a prep teammate of Oakland's Eric Chavez at Mount Carmel High in San Diego, was the third overall pick by the Tigers out of Southern California in the 1999 First-Year Player Draft.
He had 49 Major League home runs, including 18 in 2003 with the Tigers and 19 more in 2004. Munson spent the first five years of his career in Detroit before moving on to Tampa Bay in 2005. He then played one season there and two with Houston (2006-07) before appearing in one game for the A's last season.
Munson will be a left-handed bat for Triple-A Portland, possibly catching some but likely playing some third base and first base.
Munson has a career .263 average in the Minor Leagues with 127 home runs.
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.