Last week, New England Patriots wide receiver Julian Edelman was suspended for the first four games of the season for violating the league's policy on performance-enhancing substances. Edelman missed all of the 2017 seasons with a torn ACL [VIDEO]. New England finished first in the ACF East but eventually lost the Super Bowl to the Philadelphia Eagles, who won their first championship in franchise history. The Patriots receiving core last year consisted of Danny Amendola, Brandin Cooks, Chris Hogan, and others.

The unknown substance 'wasn't immediately recognizable'

In a weekly column on The MMQB, it was reported that "Edelman's results were triggered by a substance that wasn't immediately recognizable..." Albert Breer of Sports Illustrated also said that scientists are analyzing the unknown substance but have ruled out stimulants.

In an Instagram post, Edelman said: "I've taken many, many tests obviously over the course of my career and nothing like this has ever happened." Edelman is appealing his suspension and stands by not knowing what happened for a positive test against him.

It is unclear how Edelman ended up testing positive for an unknown substance

Edelman had been working with Alex Guerrero [VIDEO], Tom Brady's longtime body coach and friend. Alex Guerrero has been known to promote nutritional drug supplements. In 2004, he promoted a drug that he believed could treat cancer, AIDS, multiple sclerosis, and Parkinson's disease.

Guerrero has been investigated twice by the Federal Trade Commision.

Guerrero's statement issued to NBC Sports Boston, after learning of Edelman's suspension, said in part, "Here at our facility, we take natural, holistic, appropriate and, above all, legal approach to training and recovery for all of our clients." He also added that anyone who suggested otherwise "was just plain wrong."

With Edelman's appeal, there's question on how the NFL will justify a suspension if they do not actually know what the drug is, or if the scientists have trouble finding out what the substance was. If he is suspended he will miss the first month of the season, which includes, from Week 1 to 4, games against the Houston Texans, Jacksonville Jaguars, Detroit Lions, and Miami Dolphins.

He would lose out on about $1 million if he loses his suspension appeal. The money goes back to the Patriots, a New England policy for PED suspensions. Over the course of nine seasons, Edelman has been the recipient of two Super Bowls with the Patriots