An NBA player has been suspended for 25 days for violating the association’s Anti-Drug Program. Atlanta Hawks forward John Collins was suspended after testing positive for Growth Hormone Releasing Peptide-2 otherwise known as (GHRP-2).

According to the NBA, Collin’s will sit out a total of 25 games without pay if the decision is not overturned.

Collins, 22, was drafted in 2017 as a first-round 19th pick. He is Atlanta’s leading rebounder and second-leading scorer, averaging 17 points and 8.8 rebounds in six games since the beginning of this season in October. ESPN reported that Collins has already begun the process of appeal with the NBA Players’ Association.

Collins has since issued an apology via his Twitter account where he addressed his teammates, the Hawks Organization and fans. “I understand the impact this matter has on what we are trying to achieve together this season, and I am incredibly frustrated and disappointed in myself for putting all of us in this position. I have always been incredibly careful about what I put in my body, but I took supplements which, unbeknownst to me, had been contaminated with legal components.”