"I blame myself," Gregory told NFL.com in revealing the positive test. "And I know it sounds cliché, but there's really no one else I can blame."
Gregory also admitted that while at Nebraska, he failed two drug tests. A third would have caused him to be kicked off the team.
"I was worse at Nebraska than I've ever been at any other time of my life," Gregory told the website. "But I know how I am now. I think if teams really look at how I am now more so than the past, they'll see I'm making strides to get better, as a person and as a player."
Greogry was projected by Scout.com recently as a Top 10 pick . He's expected to be an outside linebacker in the NFL.
“My pitch to teams is that I feel like drafting me with my versatility, there are a lot more things than I can do than rushing the passer,” Gregory said at Nebraska Pro Day earlier this month. “A lot of guys you draft for one specific role. I think with me, they can mold me into any player they want. I think I showed that today and at the combine, I hope they agree with me.”
While Gregory had opportunities to standup at Nebraska, most of his work came off the edge as a 4-3 defensive end.
“I feel a little more comfortable with it, you get to have that natural athletic stance,” said Gregory when asked about being a linebacker. “I’m always excited to do linebacker drills. I thought I did really well at them today.
“I want to get to a point where any team, whether it’s a 4-3 or a 3-4 feels comfortable enough to take me. I feel like I put a lot of that on film being here, but at the same time I wanted to show my ability to play linebacker.”