Denver Broncos Pro Bowl linebacker Von Miller is facing a four-game suspension for violating the NFL's substance-abuse policy, according to multiple sources.

The case currently is in the appeals process, so it's uncertain whether the suspension ultimately will stand. No date for Miller's appeal has been set yet, a league source said.

The league has a strict confidentiality clause on such cases. If the case works the way it's supposed to, the NFL would only comment if the appeal fails.

A league source said the Broncos were aware of an issue with Miller so executive vice president of football operations John Elway and coach John Fox were not surprised by Monday's news.

"He's a different guy, but I never thought he would risk his career. Gotta help him bounce back now. Can't turn my back on him. Disappointed yet concerned about the man. Still love him, though," a Broncos player, who wished to remain anonymous, said in a text to ESPN.

At the very least, Denver will be dealing with another significant issue during training camp. Last week, the team suspended director of player personnel Matt Russell indefinitely without pay and director of pro personnel Tom Heckert for one month without pay for their recent drunken-driving arrests.

The Broncos report to training camp Wednesday. Miller will be able to participate in all of the workouts but he'd have to leave the team after its final preseason game on Aug. 29 if a suspension is upheld and he wouldn't be able to return to the team until Sept. 30.