Authorities in Harris County determined that there was not enough evidence to prosecute Sanders, who has a home in Houston. The case, according to the report, went to a grand jury on Jan. 9.
"We are aware of the media report involving Emmanuel Sanders and are looking into it," the Broncos said in a statement on Thursday.
Sanders still could face discipline from the NFL, which said the report was "under review."
The 30-year-old reeled in just 47 receptions for 555 yards and two touchdowns in 12 games this season.