The day before the Mitchell Report was to be released in 2007, Selig said, "I haven't seen the report yet, but I'm proud I did it." The report said that after mandatory random testing began in 2004, HGH treatment for athletic enhancement became popular among players, as HGH is not detectable in tests. It pointed out that HGH is likely a placebo with no performance-enhancing effects. The report included substance use allegations against at least one player from each MLB team.