Prior to the rule IV draft, the top 200 prospects eligible to the draft, as chosen by the National Scouting Bureau, are required to take part in an medical exam. Only two players tested positive for the use of a drug on the MLB's list of banned substances. It is a little ironic however, that one of the two was arguably the very best prospect out of those 200 players. In addition to Gray, righthander Aaron Blair, another day one talent, also failed his exam.
Gray tested positive for Adderall, which is used to treat ADHD. While hundreds of players have a therapeutic excuse for using Adderall, Gray did not have one. He will not receive a suspension of any nature, but he will now be more susceptible to drug tests in the future.
The reason that this test is important is because it might actually help his draft stock. General Managers have already come out and said that it will not negatively affect his stock because it is not a performance enhancing drug, but the red flag on his medical might hurt him in terms of his dollar value. This could in turn, push him past Mark Appel on Houston's draft board if they can sign him for under six million dollars. It would only make sense if Gray and Appel are perceived as equal talents to sign the cheaper player. This would also enable Houston to spread out their money allotted with this pick out to the rest of their draft. If they saved about two million here, they could then draft an elite talent who fell to them with their second pick and give that player three million. If the Astros truly want to use this portfolio approach, this would likely be more attractive than turning to a second tier talent like Colin Moran.