(SportsNetwork.com) - Denver Broncos wide receiver Wes Welker was suspended four games for violating the NFL's performance-enhancing drug policy on Tuesday, according to multiple reports.

Welker tested positive for amphetamines and lost his appeal, which took place two weeks ago.

The veteran receiver returned to practice on Monday after suffering a concussion during a preseason game against Houston.

Welker played in 13 games last season, his first with Denver, totaling 778 yards on 73 catches with 10 touchdowns.