Just days before the season opener, the Denver Broncos’ offense suffered a serious blow.

Slot receiver Wes Welker has been suspended four games for a violation of the NFL’s performance-enhancing drug policy after testing positive for a banned amphetamine, a person with knowledge of the situation told USA TODAY Sports.

The person spoke on condition of anonymity because the NFL has not yet announced the suspension. The Broncos had not been notified of the suspension late Tuesday afternoon, while coaches were deep in game planning mode for Sunday’s opener against Indianapolis.

Welker appealed the penalty two weeks ago, the person said, but it was rejected by the league.

Welker will be eligible to return to the Broncos, who have a bye in Week 4, for their Week 6 game at the New York Jets.

He is the second Bronco suspended this season. Kicker Matt Prater will also miss the first four games for a violation of the substance policy for repeated alcohol violations.

The Broncos had been hoping Welker would be cleared to play against Indianapolis after suffering a concussion Aug. 23. He participated in individual drills at practice on Monday but was not yet cleared for contact.

Welker’s concussion and pending appeal gave the Broncos time to prepare to play without him. The most likely option for the offense is that wideout Emmanuel Sanders playing more in the slot while Andre Caldwell sees more time as an outside receiver. Welker’s absence could also lead to playing time for second-round draft pick Cody Latimer and veteran tight end Jacob Tamme, who can also play from the slot.