The trial will shine a light on the use of such ballots in the nation's second-largest gambling market. The ballots have been used to swing the outcome of elections for years.
Prosecutors say "autograph parties" were held in which absentee ballots were steamed open and replaced or destroyed.
The charges stem from Small's failed primary bid to seek the Democratic nomination for mayor in 2009. Incumbent Lorenzo Langford beat Small and a third candidate.
Small turned down a plea deal that likely would have had him out of prison after a year and a half.