Koren Robinson's appeal is expected to be denied, sources have told ESPN's Chris Mortensen.
The Seattle Seahawks wide receiver is facing a four-game suspension for his third violation of the NFL's substance abuse policy.
According to sources, this positive test was for marijuana.
Seattle's No. 3 wideout Bobby Engram, one of the top slot receivers in the league, suffered a sprained left ankle Oct. 17 at New England and could be sidelined another week.
Information from ESPN's Chris Mortensen and The Associated Press was used in this report.