Christian Laettner will miss five games after violating the NBA's anti-drug policy.
Laettner, 34, was suspended five games without pay, starting with Tuesday's visit by the Houston Rockets.
The six-foot-11 forward is averaging 6.7 points, 5.3 rebounds, 2.1 assists and 23.1 minutes in 30 games, including 15 starts.
"I deeply regret any embarrassment that my actions have caused to members of my family, my teammates, my fans and the Washington Wizards organization," Laettner stated. "I accept full responsibility for my actions.
- Christian Laettner bio
An NBA player must fail three drug tests to warrant a five-game suspension.
"We're extremely disappointed that this happened." Wizards president of basketball operations Ernie Grunfeld said. "This comes as a surprise to us as the league's substance abuse policy is confidential.
"I have spoken to Christian and he is embarrassed for his family, his teammates, the Wizards organization and the fans."
Laettner is a 13-year NBA veteran averaging 13.5 points, 7.0 rebounds, 2.7 assists and 30.9 minutes over 801 games (689 starts).
The Duke product has played for the Minnesota Timberwolves, Atlanta Hawks, Detroit Pistons, Dallas Mavericks and Wizards since being drafted third overall in 1992.
"I have elected to seek professional assistance to fully educate myself as to the consequences of my behaviour to assure that these issues never interfere again with my career and my obligations to my team, my teammates and our fans," Laettner said.
"He feels terrible about the situation," Grunfeld noted. "And he's willing to do whatever he needs to do to get on the right track and get back to playing."
with files from Sports Network