Dareus was excused from training camp while he attended a hearing after being arrested in May and charged with possession of synthetic marijuana and drug paraphernalia. Dareus also faces charges in a separate case of reckless endangerment stemming from when he crashed his vehicle into a tree while allegedly racing teammate Jerry Hughes.
Dareus failed a pre-training camp conditioning test last week and remains on the active/non-football injury list.
Bills head coach Doug Marrone said Sunday that Dareus wasn't the only player to show up to camp out of shape, but he hoped Dareus would see the practice field soon.
Dareus hadn't been seen at the team's camp in Pittsford, N.Y., all weekend, and ESPN reported Monday that Dareus would arrive at training camp later in the day. ESPN also reported that he won't re-take the conditioning test until at least Thursday.
The Bills play the New York Giants in the Hall of Fame Game on Aug. 3.
"He'll be in shape and ready to play," Marrone said, via the Associated Press. "Right now he needs to focus on getting himself ready, getting himself on the field, and focus on football."
Dareus, who was a first-round draft pick in 2011, was also benched for parts of the final two games last season for breaking team rules. He finished the season with 71 total tackles and 7.5 sacks.
- Scooby Axson