ESPN first reported the pending discipline for Miller, who responded on his Twitter account, saying he had seen the reports about the four-game suspension.
"I know I did nothing wrong. I'm sure this'll be resolved fairly," he tweeted, adding he was disappointed the Broncos have to open training camp with this news hanging over them.
Miller and his agent didn't return messages left by The Associated Press.
The Broncos report to training camp Wednesday with big expectations but a growing number of off-the-field distractions, as well.
Shortly after last season's 13-3 campaign ended with a loss to Baltimore in the divisional playoffs, none other than Miller guaranteed a Super Bowl title for Denver for the 2013 season. Then, just last week, left tackle Ryan Clady signed a new contract and, during interviews to discuss the deal, said it was, "Super Bowl or bust, for the most part" for Denver.
It's the kind of talk, at least in public, that Peyton Manning and coach John Fox disdain. It is, however, in line with what Las Vegas says (At odds ranging between 9-2 and 6-1, the Broncos are widely listed as the favorites to win the Super Bowl) as well as the roster Executive Vice President John Elway has assembled. He added Wes Welker to Manning's receiving corps, shored up the line with free agent guard Louis Vasquez and used a second-round draft pick to add Wisconsin running back Montee Ball to the mix, as well.
But not all the offseason news has been positive for the Broncos. Elway's top two assistants, Matt Russell and Tom Heckert, are each serving suspensions after arrests on drunken driving charges an embarrassing run of news that deprives the Broncos of their top personnel men at a time when personnel decisions are paramount.
The other bit of bad news for Denver this offseason was its inability to keep pass-rushing defensive lineman Elvis Dumervil because of a mix-up with a fax machine that kept the team from receiving his signed contract in time.
The Broncos felt good about replacing Dumervil and his 11 sacks last season, but in large part, the comfort came because they had Miller, who has 30 sacks over his first two NFL seasons, lining up on the other side.
Without Miller, the Broncos defense would be missing its best pass rusher for its first four games against Baltimore, the New York Giants, Oakland and Philadelphia. If suspended, Miller would be able to participate in all of the workouts at training camp but would have to leave the team after its final preseason game on Aug. 29.