Hock missed much of last season because of injury
Wigan and England forward Gareth Hock has tested positive for cocaine and been provisionally suspended by the Rugby Football League.
A statement on the club website said the 25-year-old second rower tested positive for a prohibited substance after the game with Salford on 5 June.
If found guilty Hock - whose B sample will be tested on 30 June - will face a two-year ban from the sport.
Hock signed a new contract in May 2008, keeping him at the club until 2011.
"The RFL can confirm that under its anti-doping rules it has charged Wigan Warriors' Gareth Hock with an anti-doping rule violation," read a RFL statement.
"This was after the RFL was informed by UK Sport on Monday, 22 June that there had been an adverse analytical finding in a specimen provided by Hock following the Wigan versus Salford game on 5 June. The sample contained Benzoylecgonine, a metabolite of Cocaine.
"The RFL condemns the use or distribution of prohibited substances or methods as defined by the World Anti-Doping Agency (Wada) prohibited list."
A Wigan statement read: "The club was informed of the situation on 22 June and joins with the RFL and UK Sport in deploring and condemning the use of drugs in sport including so-called recreational drugs."
Wigan-born Hock came up through the club's academy system and was named Super League's Young Player of the Year in 2003.
He played for Great Britain in the 2006 Tri-Nations and was part of the England team who beat France earlier this month.
Knee ligament and shin problems kept him out for 15 months at the end of 2006, and in 2008 he made just 19 appearances for the Warriors because of injury and suspension, being banned twice.