Pre-draft coverage ahead of the NFL Draft's first round, which will kick off tonight, has largely focused on the two quarterbacks at the top, Florida State's Jameis Winston, and Oregon's Marcus Mariota. The biggest talent in this draft may not be a quarterback at all though, even if teams are afraid to pick him.

Nebraska pass rusher Randy Gregory has become the latest victim of shifting opinion, and negative stories are cropping up about his mental makeup. It couldn't come at a worse time, even if his issues haven't exactly been spelled out.

An NFL.com report has surfaced that vaguely details the concerns of several coaches, executives and scouts' doubts about Gregory's ability to "handle the mental rigors of professional football."

One NFC executive said he thinks where Gregory lands is important, and despite his talent some teams would be right to stay away from him.

"It all depends on the organization, and what they have in place for him. There are quite a few players that have issues. It's where you place football character over the things he can't control. That's the big thing to me."

Other quotes steer the conversation into the realm of medical issues. The report mentions he is "not a bad kid," and comes from a "solid background." Yet this quote doesn't seem like it comes from someone eager to add Gregory to their organization.

"At some point, the risk meets the reward, especially at the bottom of the (first) round -- those are good teams," one scout said. "They miss, it's not a big deal. But the top 20 picks of each round, it's tough. He's either gonna be a good player or he's not gonna be in the NFL. He comes from a good home, he's a smart kid.

"How do you wanna deal with it?" the scout continued. "Do you wanna work with him? Can you do the off-the-field stuff to manage it?"

What's really not in doubt though, is Gregory's ability to impact games. In his first season at Nebraska, Gregory notched 10.5 sacks, and followed that up with an eight-sack campaign in 2014. In total he's registered 120 sacks over two seasons, and hit opponents for 25.5 tackles for loss. At the Combine he was viewed as a bit undersized, but raw talent tends to make up for size issues.

Gregory has plenty of talent, so his amorphous issues will be an intriguing plotline as the Draft unfolds. With many teams grading him as a Top 5 talent, he may slide and become an enormous, if high-risk, value.