http://mlb.mlb.com/news/article.jsp?...ticle_26059392

Competitive Balance Lottery to shake up Draft
Small-market, low-revenue teams to get chance at extra picks

The first lottery will take place in July, after the 2012 Draft signing deadline has passed. The 10 smallest-market teams and the 10 lowest-revenue teams will be placed in the lottery to have a chance to win one of six extra picks in 2013. This doesn't mean there will be 20 teams in the lottery. There will be plenty of crossover, with the expectation of having 13 teams involved

The teams that will be eligible for the first lottery are the D-backs, Orioles, Indians, Royals, A's, Pirates, Padres, Rays, Reds, Rockies, Marlins, Brewers and Cardinals.
The odds of winning a Draft pick in this lottery will be based on each team's winning percentage in the previous season. The half-dozen picks will be made at the conclusion of the first round, but after the compensation picks for free agents.