Arenas, who also sat out Friday's practice with leg soreness, was able to play in the team's scrimmage later that night.
"Gil went last night, but tweaked his ankle, so he did not go today," coach Flip Saunders said.
Andray Blatche also played in Friday night's scrimmage, his first since having surgery to repair a broken foot in June. Saunders said that the 6-foot-11 starting power forward "looked OK" as he works on getting back into shape.
"He's going through every drill and doing all the stuff," Saunders said. "He's had no restrictions on what he's doing."
Saunders stopped the scheduled three-hour practice after two hours with the team practicing largely in the dark. The coach described the session as more of a "cerebral" practice, saying the team focused on situational plays. Despite the outage, Saunders said that the team had pretty good concentration and then joked about how well the team was able to shoot.
"I guess you can say we shot the lights out," Saunders said.
Al Thornton, who tweeted on Thursday night that he had "just literally got hit by a car walking," spoke to the media for the first time about the incident.
The 6-8 forward said he was leaving practice on the rainy night and walking up a hill in a parking area on the George Mason University campus where the team is conducting training camp when he saw a car driving toward him.
"I assume she saw me when I was walking up the hill, but she didn't," Thornton said of the female driver he believed was a student. "As soon as she got toward me, she knicked my knee a little bit, but I jumped on top of her car in the process. It was kind of crazy."
Thornton said the car was moving around 20 mph and that he thought the driver was in a rush.
"I think she was late for class," he said.
Thornton was incredulous that the driver hadn't seen him.
"As soon as I jumped on top of the hood, I was looking like directly in the window," Thornton said. "I was like 'You didn't see me? What are you doing? A tall black guy. You didn't see me?' "
Thornton is competing to be the Wizards' starting small forward, and knows that the accident could have been much worse.
"Seriously, that could have been my career," he said.