Nick Calathes will be suspended 20 games for a violation of the NBA's Anti-Drug policy.

The suspension will begin immediately.

A source says Calathes tested positive for Tamoxifen, which was part of an over-the-counter athletic supplement he had used.

The NBA's lab results showed no traces of testosterone or PED in the supplement.

"There was no intent here," said a league source.

David Joerger and the Memphis Grizzlies will be without Calathes in the playoffs.