The statement never mentions Trout by name but it is clear who MLB and the MLBPA are referencing. MLB issues about 100 TUEs each season, allowing players to use otherwise banned substances for medical purposes. The vast majority of TUEs cover stimulants prescribed for ADHD.
Earlier this week, the internet was abuzz after the Astros were punished for stealing signs during their 2017 World Series championship season. Social media was flooded with carefully curated video and screen grabs claiming to be evidence of cheating beyond what was described in the report.

To make matters worse, Reds pitcher Trevor Bauer reached out to Yahoo!’s Daniel Roberts saying players are aware of Trout’s HGH exemption and simply don’t care. Bauer then walked back his comments and said players would not care “if” Trout has an exemption, which sounds like something he would say after MLB, the MLBPA, or Trout’s lawyers got in touch with him.

The allegation against Trout was made Thursday by David Brosius, son of longtime big league player and coach Scott Brosius, who posted on Instagram that Trout uses a “loophole” to take HGH for a thyroid condition. Brosius temporarily deleted his account soon thereafter, then issued an apology saying there is “no evidence” Trout is using HGH. “The MLB-MLBPA Joint Drug Prevention Program is administered independently and transparently by the parties’ jointly appointed Independent Program Administrator (IPA). In his annual report, the IPA discloses publicly the Therapeutic Use Exemptions (TUEs) granted to Players during the prior season. Since the inception of the Program, no Major League or Minor League player has ever received a TUE for, or otherwise received permission to use, Human Growth Hormone (HGH).” 
MLB launched random, in-season testing for HGH in 2013, so Trout has been tested throughout his career. More important: If Trout (or any player) has a TUE to treat a medical condition, it is none of our business. Personal medical conditions are not baseball injuries. Those are between the player, his doctors, and MLB.
Lost in the sign-stealing madness was a serious accusation that Los Angeles Angels star Mike Trout has a medical exemption to use human growth hormone, a banned substance. The allegation is serious enough that MLB and the MLB Players Association released a joint statement Friday night shooting it down.