The estimates of the numbers of NFL players that use HGH have varied from as high as 50 percent to as low a five percent or less. In a conversation with a longtime veteran this week, I got maybe the most levelheaded estimate of them all.

His belief is that 15 to 20 percent of the NFL is using and he would "shade towards the lower end." He's had conversations with several players who use the drug and those conversations invariably turn to two things: the benefits of the drug and how many use it.

"It's not a large number of players that use it," he said, "but it's not a tiny amount."

If 15 percent of the NFL uses that would be approximately 400 of the 2,700 total players.

What the player said next was maybe most interesting. He's noticed a shift in attitudes in NFL locker rooms towards HGH. Players have watched what's happened in baseball, as that sport has been swallowed alive by PEDs, and it's scared the hell out of them.

Players have fully bought into the mindset that one of the few things that can kill the cash cow that is the NFL is the perception the league is drugged up.

That's led to a seismic shift, I'm told, to now where almost all NFL players want HGH testing. "The only players who don't want HGH testing are the players using HGH," the veteran said.

Another longtime veteran added: "Yes, I want (testing). I don't want to fight through injuries while someone gets artificial help recovering or gaining strength." His guess was ten percent of the NFL uses HGH.

"The guys that are using it need to get put on full blast," Raiders defensive end Lamarr Houston told the NFL Network this week.

"For me, I'm happy. I don’t take that stuff, so I'm more than happy to do it," linebacker Jon Beason said. "The guys who are taking it, now if they get caught it's an even playing field. It's already hard enough to make it to the league, stay in the league and stay healthy in the league…I think it's a good thing, so I'm looking forward to it an more than willing to comply with whatever the league and NFLPA comes up with."

"I know I wouldn't have a problem with it because it levels the playing field," 17-year veteran Tony Gonzalez told CNBC, when asked about HGH testing. Why wouldn't you want something like that? We have to give blood anyway so might as well test it for HGH."

The NFL and union continue to negotiate to test players starting this season. Both sides remain optimistic though it's unlikely an agreement is reached this week.

What's become clear is that, in many ways, the players are pushing for HGH testing as much as the NFL is.