Denver Broncos linebacker Von Miller's appeal hearing on a four-game suspension for violation of the NFL's substance-abuse policy will not be conducted Thursday, as tentatively scheduled, according to sources.

The Broncos' Von Miller vowed to stay in top physical condition while he serves his suspension. John Leyba/Getty Images

Miller's case has "complications" that has resulted in the league and NFL Players Association working to resolve on the player's behalf, the sources added. No other specifics were provided.

The NFL has not announced any suspension for Miller because his appeal is pending.

Despite the postponement of Miller's hearing, he was not at the final day of training camp Thursday.

With 30 sacks over the past two seasons, including 18.5 in 2012, Miller would leave a significant hole in the Broncos' defensive plan.

"We're prepared for any possible scenario,'' Broncos quarterback Peyton Manning said. "That's how you have to be. If you get all wrapped up into one outcome and it doesn't end up turning out that way, you don't really have a Plan B. Today was a good practice on the possibility that he may not be here. If that's the case, that's not going to be an excuse for our team and we have to find a way to do our job. But we certainly hope that he is here.''

If he loses his appeal, he'll miss games against the Baltimore Ravens, Oakland Raiders and Philadelphia Eagles at home and New York Giants on the road.

Miller, meanwhile, was arrested Sunday at the Centennial Gun Club, a facility that's near the Broncos' practice facility in south suburban Denver, on an outstanding traffic warrant for failing to appear for a court appearance on Dec. 31. During an October traffic stop, was charged with careless driving, driving without a license and no proof of insurance.

Miller was released on a $1,000 bond Sunday, an off day for the Broncos.

ESPN.com's Jeff Legwold contributed to this report.