Former Major League outfielder and designated hitter Jeremy Giambi passed away on Wednesday, according to his agent Joel Wolfe. He was 47 years old.

Giambi spent the best seasons of his career with the A's, but he was selected by the Royals in the sixth round of the 1996 Draft out of Cal State Fullerton, where he was a member of the 1995 College World Series championship team.

Giambi moved up quickly through Kansas City’s farm system and reached Triple-A within two years, posting a 1.103 OPS with 20 home runs in 96 games for Omaha in 1998.

The Royals called Giambi up and he made his big-league debut on Sept. 1, 1998, against the Blue Jays, going 0-for-2. He appeared in 18 games for Kansas City that year, hitting .224 with a pair of homers. He began the 1999 campaign at Triple-A, but wasn’t there for long after hitting 12 home runs with a 1.157 OPS in 35 games.

In 90 games with the Royals in 1999, Giambi hit .285 but slugged only .368. On Feb. 18, 2000, Kansas City traded Giambi to the A’s, where the California native joined his brother, Jason, who was the starting first baseman. Jeremy played in 104 games during his first season with the A’s and posted a .761 OPS with 10 homers.

The following season, Giambi had a breakout performance at the plate, slashing .283/.391/.450 with 12 homers in 124 games to help Oakland win the American League Wild Card spot. He went 4-for-13 with a double and two RBIs in the AL Division Series against the Yankees, which the A's lost in five games.

In 2002, Giambi continued to perform well at the plate, posting an .862 OPS with eight home runs through 42 games before being traded to the Phillies. He was even better for Philadelphia, slugging .538 with 12 homers in 156 at-bats down the stretch. He finished that season with a .919 OPS and a career-high 20 homers.

The 2003 campaign was Giambi’s last in the Majors, and it came with the Red Sox after he was traded to Boston the previous December. He struggled with the Red Sox, slashing .197/.342/.354 in 156 plate appearances.

Giambi was best known for his time with Oakland, where he and his brother helped propel the A's to consecutive postseason appearances at the turn of the century.

“We are heartbroken to learn of the passing of a member of our Green and Gold family, Jeremy Giambi,” the A’s tweeted. “We offer our condolences to Jeanne, Jason, and his family and friends.”