Dallas Cowboys linebacker Rolando McClain has been suspended for four matches by the NFL.
The 25-year-old signed a one-year deal with the Cowboys during the off-season after a successful 2014 campaign with the club.
However, he will now miss the first four games of the 2015 season after violating the NFL's policy regarding substances of abuse, but will be eligible to return in week five for his side's clash against the New England Patriots.
"I apologise to my family, the Cowboys organisation, my teammates and Cowboys fans for my mistake," McClain said in a statement released by the NFL Players Association.
"I will not break the rules of my profession in the future, and I regret my error. I look forward to returning to the field on week five, when I hope to help my team beat the Patriots."
McClain recorded 81 tackles, one sack and two interceptions last season.