Wes Welker is facing a four-game suspension for violating the NFL's performance-enhancing drug policy, according to published reports.

ESPN reported the violation had to do with amphetamines.

The Broncos didn't immediately return a message from The Associated Press requesting comment Tuesday.

NFL Media reported Welker was notified Tuesday he had lost his appeal, which was heard two weeks ago.

Welker returned to practice Monday for the first time since suffering a concussion Aug. 23. It was his third concussion in 10 months.

Welker caught a career-best 10 TD passes last year.

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