Of the top 40 Dominican prospects identified by Major League Baseball this year, only five have signed since July 2, a date set by baseball when many 16-year-olds become eligible to sign contracts. The new rules were imposed after a stream of scandals, including disclosures that players who received substantial bonuses were older than they claimed or were using steroids. For the first time this spring, Dominican prospects were required to undergo testing for steroids and to prove their age and identity before signing. Thirteen of the 40 prospects failed steroid tests — a staggering number considering that only 2 of roughly 1,200 major leaguers tested positive this year. Investigators for baseball are still trying to confirm the age of seven prospects and have concluded that they will be unable to verify the ages of three others. Ten players and their parents have taken DNA tests in the hopes of proving the players’ identities.