(The Sports Xchange) - Dallas Cowboys defensive end Randy Gregory, already serving two suspensions totaling 14 games for multiple violations of the NFL's drug policy, now may be facing a year-long suspension.

Gregory has failed another drug test, sources informed of the situation told the NFL Network.

Gregory served a four-game suspension to start the season for his first substance-abuse violation and is currently serving a 10-game suspension for violating the league's policy for a second time.

The defensive end's next suspension will be for a full year. The report would mean he has failed a sixth test -- his fifth while a member of the Cowboys. The Nebraska product tested positive for marijuana at the NFL Scouting Combine in 2015.

Gregory checked himself into a treatment center during the summer but reportedly later left the facility and missed a scheduled drug test. A missed test carries the same weight as a failed test.

Gregory, who turns 24 later this month, was placed on the reserve/did not report list and did not take part in training camp.

The Cowboys selected Gregory late in the second round in 2015 with the 60th overall pick. He played in 12 games last season but had little impact, compiling 12 tackles with no sacks.

(Editing by Larry Fine)