Sheen had been charged with second-degree assault, menacing and criminal mischief after allegedly brandishing a knife at Mueller Dec. 25, 2009, in Aspen, Colo.
Sheen is eight days away from completing his probation. The Aspen District Attorney's office told TMZ.com that it's aware of the Plaza Hotel incident but won't take any action unless it receives facts showing that Sheen violated his probation.
In July, Sheen took time off from his hit television show voluntarily to enter a rehab facility -- for the third time in his career -- "as a preventive measure," according to his rep Stan Rosenfield.
At Sheen's sentencing in August, his attorney, Yale Galanter, said the actor had already spent 93 days at the Promises rehabilitation facility this year, and the center could choose to credit that time toward his sentence.
"Credit for time served is absolutely on the table," Galanter said. "How much credit he gets is up to Promises."
Galanter also said that Sheen and Mueller had been sober for months.
Substance abuse and anger issues aren't Sheen's only woes. Twice this year, cars stolen from his Hollywood Hills home have been found crashed and abandoned in a ravine.
ABC News' Michael S. James and WABC's Mark Crudele contributed reporting.