Though spending the majority of his time with the Oakland's Double-A Midland RockHounds and Triple-ASacramento River Cats, "Badge" (short for "Badger," a nickname for his ample body hair) had a .379 OBP over his first 4 years. Brown made his Major League debut on September 3, 2006, against the Baltimore Orioles. He had 3 hits in 10 AB, including two doubles, and a .364 OBP in the Major Leagues for the 2006 season.
Brown was designated for assignment by the Athletics on May 23, 2007 and subsequently outrighted to the minors.
On February 15, 2008, Brown announced his retirement. Brown was the team's third-ranked catcher behind Kurt Suzuki and Rob Bowen and was unlikely to make the major league roster.