Edelman received the suspension after violating the NFL's performance-enhancing substances policy.
The MMQB's Albert Breer reported in June the substance for which Edelman tested positive "wasn't immediately recognizable."
According to ESPN's Dan Graziano, that was part of the basis for his appeal. The appeal also centered on an alleged "mishandling of the documentation and delivery" of his test results.
With Edelman's suspension upheld, NESN's Zack Cox reflected on what it means for the Patriots:
The suspension is also a setback for Edelman as he returns from a season-ending torn ACL. His last competitive game was Super Bowl LI in February 2017, when he caught five passes for 87 yards in a 34-28 win over the Atlanta Falcons.
The Patriots added Cordarrelle Patterson and Jordan Matthews in the offseason and selected Braxton Berrios in the sixth round of the NFL draft. Kenny Britt is also entering his first full season in New England.
With Edelman out for four games, the opportunity is there for somebody to step up and play a starring role in the Patriots' passing game.