Born in West Palm Beach, Florida, he is of Cuban descent as his father left Cuba during the Fidel Castro revolution.
Before being drafted, he graduated from Jupiter High School in Florida, and then attended Middle Georgia College.
Abad opened 1998 with Triple-A Pawtucket Red Sox, where he hit .307 with 16 home runs and stole 10 bases.
In between, Abad had three productive seasons for the Navegantes del Magallanes of the Venezuela Winter League between 1996 and 1999 and also played in the Caribbean Series.
He started with their Triple-A club, the Sacramento River Cats, where he had one of his best minor league seasons, hitting .301 with 19 homers and 92 runs batted in in 124 games.
Abad made his debut with Oakland late in September, appearing as a pinch hitter for Jeremy Giambi, resulting in a pop fly out.
He played the entire season with Triple-A Buffalo Bisons, collecting a .293 average with 85 RBI and a career high 20 home runs.
In 2008, Abad was named the hitting coach for the Yakima Bears, a Low-A affiliate of the Arizona Diamondbacks organization.