Atlanta Hawks forward John Collins has been suspended 25 games after testing positive for a banned substance under the NBA’s steroids and performance-enhancing drugs program, the league announced Tuesday.

Collins tested positive for growth hormone releasing peptide-2 (GHRP-2), a growth hormone stimulant that can lead to increased muscle mass.

The suspension will take effect immediately and sideline Collins until Atlanta’s Dec. 23 visit to the Cleveland Cavaliers. Given that his suspension is without pay, Collins will forfeit more than $610,000 of his $2.7 million salary.

The 22-year-old forward is averaging 17 points, 8.8 rebounds and 2.0 blocks this season, making him the Hawks’ leading rebounder and second-leading scorer. Best known for his highflying finishes, the 2017 first-round draft pick has refined and expanded his offensive game and emerged as a potential star during his three seasons in Atlanta.

“We are disappointed to learn that John put himself in an unfortunate situation and violated the league’s anti-drug policy,” Hawks General Manager Travis Schlenk said in a statement. “We hold ourselves and each of our players to a high standard, and we are committed to supporting John as he learns from this setback and continues to grow as both a player and a person. We believe that he is truly remorseful for his actions. We will provide John with support on and off the court while we look forward to his return to the team.”

Collins’s inside-outside partnership with second-year guard Trae Young is at the center of the Hawks’ long-term planning, and his absence will leave Coach Lloyd Pierce scrambling to replace his production. This is no small void: Collins has led Atlanta in minutes as the most proven member of a young frontcourt that has added multiple new pieces as the organization retools its roster around Young’s deft playmaking and Collins’s finishing.

To fill in the gaps, Pierce will need to lean more heavily on center Alex Len, who has been dealing with a rib injury. The second-year coach can also turn to Jabari Parker and Damian Jones, two summer signings, and rookie big man Bruno Fernando from Maryland to fill minutes at power forward and center. Alternatively, Pierce could shift more toward small-ball lineups that use De’Andre Hunter, a 2019 top-five pick, at power forward. There are no great solutions for a young Hawks team that is on a three-game losing streak and will host the San Antonio Spurs, Chicago Bulls and Sacramento Kings this week before embarking on a demanding five-game road trip through the Western Conference.

“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,” Collins said in an apology issued to ESPN. He added that he had ingested a supplement that "unbeknownst to me had been contaminated with an illegal component” and expressed plans to appeal his suspension.

The NBA’s comprehensive anti-drug program includes random testing for marijuana, steroids and drugs of abuse. A positive test triggers a range of consequences — from a warning to a lifetime ban — depending on the substance, with steroids, performance-enhancing drugs and diuretics leading to an automatic 25-game suspension on the first offense.

Collins joins Phoenix Suns center Deandre Ayton and Brooklyn Nets forward Wilson Chandler as the third player since August to face a 25-game suspension for performance-enhancing drugs, an unusual rash of violations for the NBA. Then-Washington Wizards guard Jodie Meeks also tested positive for GHRP-2 in 2018.

Read more: