Tristan Thompson was suspended 25 games by the Cavaliers for breaching the NBA's anti-drug policy.
The 32-year-old backup center was suspended without pay after testing positive for “ibutamoren, a growth hormone, and SARM LGD-4033, commonly used by bodybuilders and weight lifters for muscle enhancement,” according to ABC News. 
When the Cavs play Houston on March 16, Thompson can return.
Team statement: “The Cleveland Cavaliers fully support the NBA/NBAPA Anti-Drug Program, and we are disappointed in the recent news surrounding Tristan Thompson. “His absence from games will affect our team. Tristan has our support during this suspension.”
The NBA, NCAA, and WADA restrict ibutamoren and LGD-4033 (Ligandrol), according to Business Insider.
Thompson can travel and practice while suspended.
ABC News reports that his sole rule is leaving the venue two hours before gametime.
Thompson spent his first nine NBA seasons with the Cavaliers. The club re-signed him as a free agent before this season.
Thompson has switched clubs, playing for Boston, Sacramento, Indiana, Chicago, and the Lakers.