Atlanta Hawks ace John Collins has been suspended for 25 games after testing positive for a growth hormone, the NBA said Tuesday.

The 22-year-old power forward was hit with a suspension after growth hormone releasing peptide 2 (GHRP-2) was found in his system, the league said in a statement.

The suspension is effective immediately, meaning Collins will miss Atlanta’s clash with the San Antonio Spurs later on Tuesday.

“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 us in this position,” Collins said in a statement.

“I have always been incredibly careful about what I put in my body, but I took a supplement, which unbeknownst to me, had been contaminated with an illegal component,” added Collins, who has averaged 17 points and 8.8 rebounds per game this season.

Collins’ suspension comes just weeks after Phoenix Suns center Deandre Ayton was banned for 25 games for testing positive for a diuretic.

In August, Brooklyn Nets veteran Wilson Chandler was hit with a 25-game suspension for testing positive for Ipamorelin, another form of growth hormone.

The NBA, like most other major professional US sports leagues, is not a signatory to the World Anti-Doping Code, instead running its own anti-doping program.