Stillwater, Okla. ? The attorney for former Oklahoma State coach Sean Sutton entered a not guilty plea to four felony drug-related charges Tuesday and said his client is in a treatment center.

The attorney, Trace Morgan, explained the reason for Sutton’s absence at the arraignment to Payne County Special Judge Michael Stano, who set an April 5 hearing date. Morgan later declined comment to reporters.

Sutton, 41, was arrested Thursday after agents from the Oklahoma Bureau of Narcotics and Dangerous Drugs said he picked up a shipment of painkillers under another person’s name.

Authorities said the package contained about 40 pills, which included the anti-anxiety drug clonazepam and two forms of the stimulant Adderall. An affidavit from bureau Agent Brian Surber said Sutton told the agent he had obtained the drugs from people he had met while in an inpatient rehabilitation program.