West Ham midfielder Shaun Newton was suspended for seven months on Wednesday after testing positive for cocaine.
The Football Association (FA) said the 30-year-old Newton tested positive following West Ham's FA Cup 1-0 semi-final win over Middlesbrough on April 23. Newton came on as an 89th-minute substitute. He didn't play in the final, which West Ham lost on penalties to Liverpool.
The ban began on May 20, the day when he was suspended by the club.
"He will be subject to target testing throughout the period of the suspension," the FA said in a statement.
West Ham said Newton didn't travel with the club when the Hammers left on a preseason tour of Sweden on Wednesday.
"I have let down my family, my friends, the club and its supporters," Newton told the London Evening Standard newspaper. "It was an isolated incident, but I must face up to my responsibilities and I will abide by whatever the board decides."
West Ham's board will decide on Newton's punishment at a meeting next month, but manager Alan Pardew said he wouldn't be sacked.
"Our instinct is to support Shaun and his young family and give them all the help and encouragement we can," Pardew said. "We will work with him to help him get through this period, and ensure that he comes through the other side."
"I have seen at first hand the emotional and personal hell that Shaun Newton has been through in recent weeks, and our priority must be to help him -- not abandon him. I hope his experience serves as a lesson to any sports-person," he said.
Newton played 30 times for West Ham last season. He played three times for the England Under-21 side. He began his career at Charlton, where he played from 1993 to 2001. He moved to Wolves until 2005 before joining West Ham.
The FA said it tests 1,600 players at all levels of soccer, both in and out of competition, each season.
Earlier this month, Chris Cornes was banned for six months after testing positive for cocaine while playing for Wolverhampton.