ESPN Cowboys reporter Todd Archer explains why it wouldn't be surprising if Dallas parted ways with Rolando McClain, considering the salary cap and his 10-game suspension for violating the league's substance-abuse policy. (0:59)

OXNARD, Calif. -- Dallas Cowboys linebacker Rolando McClain has yet to report to training camp, and there are real questions as to whether he will play in the NFL again.

Sources confirmed that McClain's recent 10-game suspension is not for a failed marijuana test but for an opiate commonly referred to as "purple drank" -- a combination of Sprite, cough syrup and codeine. Other sources said the suspension was not marijuana-related.

"Even we don't know all the details," Cowboys executive vice president Stephen Jones said when asked about McClain as he walked off the field after Tuesday's walkthrough. "We just don't know."

When asked whether McClain's career is over, coach Jason Garrett said, "We're focused on the guys who are here."

Cowboys linebacker Rolando McClain, who has yet to report to training camp, was suspended 10 games after testing positive for "purple drank," sources told ESPN. Matthew Emmons/USA TODAY Sports

McClain and Randy Gregory, who sources said is facing a potentially longer suspension for another violation of the substance-abuse policy, were placed on the reserve/did not report list at the start of training camp. Per the collective bargaining agreement, the players are subject to fines of $40,000 each day they are absent.

The Cowboys knew of Gregory's absence before camp as he checked into a treatment facility, according to sources. McClain was expected on the team's flight to California last week and did not show.

Owner and general manager Jerry Jones said last week that there are "nuances" involving McClain's situation but would not elaborate. If the Cowboys release McClain, he would count $750,000 against the salary cap. Because the suspension does not start until the season starts, he technically has not violated his contract.

Whether McClain wants to continue to play football is unknown. He has retired twice in his career before joining the Cowboys in 2014. He participated in the early part of the team's offseason program but did not last long.

He did not show up for organized team activities earlier this offseason. He reported to the mandatory minicamp in June but did not practice because he was not in condition. According to sources, he was overweight at the start of the offseason conditioning program and he had not lost weight when he arrived for minicamp.

McClain, who missed the first four games last season because of a suspension, is in Stage 3 of the substance-abuse program. According to the policy, a player is subject to a suspension of one year if he does not enter a treatment facility at the medical director's request. It's not clear whether that request has been made of McClain, and efforts to reach McClain's agent, Pat Dye, have been unsuccessful.