Shortly after news broke that he had been issued a four-game suspension for violating the NFL's performance-enhancing drug policy, Patriots wide receiver Julian Edelman took to Instagram to express his confusion over just how this had happened. 

"I don't know what happened," Edelman wrote. "I've taken many, many tests obviously over the course of my career, and nothing like this has ever happened. I apologize to the Kraft family, my coaches, teammates and fans."

Now we know why he was so confused. According to a report from The MMQB's Albert Breer, the substance for which Edelman tested positive was so unrecognizable that scientists are still analyzing it. 

I know what Julian Edelman posted on Instagram in the wake of the suspension news ("I don't know what happened") came off as a little weird, but there is an explanation for it. I was told Edelman's result was triggered by a substance that wasn't immediately recognizable, and there are scientists analyzing it. And as to the timing, the test did happen during the offseason (a couple months ago), which means it's not for any kind of stimulant. You might remember the rash of players saying they got popped for Adderall — the rules have changed now so that offseason use of stimulants falls under the substances of abuse policy, rather than the PED policy.

Well that's ... interesting?

Given the way these things tend to leak out, it seems likely that we'll get more information at some point, but we don't really know when that'll be. As Pro Football Talk's Michael David Smith noted, "In 2003, four Raiders players tested positive for tetrahydrogestrinone, or THG, a substance that wasn't initially detectable in urine tests. It was only after the lengthy Balco investigation that drug testers re-tested stored urine samples and detected the substance."

If more players test positive for unknown substances, or the same substance for which Edelman tested positive, maybe that'll help shed more light on the situation.