Thompson was originally signed as an undrafted free agent by the Anaheim Angels on 13 February 2002.

However, after allowing five earned runs on four hits in his only outing against the Texas Rangers, Thompson was optioned to the Triple-A Salt Lake Bees to make way for Shields.

On 10 September 2010 Thompson picked up his first major league win after the Angels went into extra innings against the Seattle Mariners.

Thompson made his only Australian Baseball League appearances in the 2010–11 season pitching in three games for his native Sydney Blue Sox.

[1] Thompson injured himself prior to breaking camp with the Blue Jays and is still listed as inactive (not released or retired) with the AAA team as of 2019.