Warwickshire confirmed the suspension which follows the news last week that he had tested positive during their Championship match against Hampshire at Edgbaston last month.
The 35-year-old Piper will appear before an England and Wales Cricket Board (ECB)disciplinary panel later this week after testing positive for a recreational drug.
A statement from Warwickshire declared: "The club are now in a position to confirm that the England and Wales Cricket Board have received formal notification from UK Sport that Keith Piper has provided a positive test sample for a banned substance.
"The player will attend an ECB hearing on Thursday of this week.
"The player has been suspended pending the outcome of the hearing, after which a formal statement will be issued to clarify the situation."
If the panel finds against him, Piper's career would likely be over as he has already failed an internally-conducted drugs test, in 1997, for which he served a one-match ban.
Piper is the third Warwickshire player to be in such a position.
Paul Smith and Graham Wagg have also served drugs-related bans. Last season Wagg was given a 15-month ban by the ECB after testing positive for cocaine, and suffered a double blow when his Warwickshire contract was duly terminated.