Von Miller is facing a six-game suspension for violation of the league's substance policy, according to league sources, but the sides still are negotiating as representatives of the Denver Broncos linebacker are trying to get the ban reduced to four games.

The announcement is expected this week, and could come as early as Monday.

Miller is not likely to go forward with an appeal, though all sides were trying to finalize the suspension's conditions.

Miller met last Thursday with the NFL Players Association with some hope he could have the suspension reduced to four games, sources said, but another source familiar with the process was convinced it will be at least a six-game suspension.

In the test that triggered the suspension, multiple sources say Miller was flagged for a "diluted sample." It happened after Miller was asked to provide a test before an offseason workout/practice and the sample was spilled, by Miller, before it was given to the collector. Miller was then asked at that time to provide another sample and he could not.

Von Miller likely will get a six-game suspension for violating the NFL's substance-abuse policy but the linebacker is trying to get the ban reduced to four games. John Leyba/Getty Images

He then participated in the workout, drinking fluids throughout the activity. Miller then provided a sample that was used in the test following the workout.

At the meeting with NFLPA officials Thursday in Washington, D.C., multiple sources say discussions were held over whether to challenge Miller's positive test in 2011, for marijuana and amphetamines, as part of his appeal. The flagged samples came following the NFL lockout that kept players away from team facilities until training camp opened. Miller has also argued prescribed medication provided the positive result for amphetamines.

Former Broncos linebacker D.J. Williams also appealed a suspension, last year, that came after a spilled sample. According to court documents from a lawsuit filed following his six-game suspension in 2012, Williams had already failed two tests in his file when giving a sample as part of the random testing program, the bottle fell from his waist area as he was giving the sample. The court documents said Williams then appeared to try to kick the bottle. When his samples were analyzed he was flagged for providing "non-human'' urine.

He was then suspended six games for substance-abuse policy and three more for the personal conduct policy.

The Broncos open the regular season Sept. 5 against the Baltimore Ravens in a Thursday night game that kicks off the season.

Miller, 24, had 30 sacks in his first two seasons, including 18.5 in 2012.

Broncos coach John Fox said Monday that it's business as usual for the team and Miller until they are notified it's not.

Fox said following Monday's practice the Broncos have not been notified of a suspension for Miller and as a result he continued to practice with the first-team defense.

"There's really no latest. We're aware of reports and sometimes they're erroneous because we'd probably find out before other people.''

Asked how long the team has been aware that the suspension could be six or eight games rather than the four that had been widely reported, Fox said:

"We've haven't been aware of really any of it, to be honest with you. We don't know the suspension. There is no suspension and at which time there is, we'll report that. But anything else right now, really, is talking heads.''

Also Friday, Miller was listed among a large number of possible witnesses for the prosecution in a trial of a man facing the death penalty for allegedly killing five people in Denver last year.

The witness list was made public Monday and obtained by KUSA, Denver's NBC affiliate and a Gannett property.

Miller is on the list as an acquaintance of a friend of the defendant, Dexter Lewis.

Denver Broncos spokesman Patrick Smyth told USA TODAY the team has been aware for a while that Miller could be called as a witness and that "He has no direct involvement in the case."

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