Nets G/F Allen Crabbe suffered a sprained ankle on Wednesday at the end of the team's practice, according to Greg Logan of Newsday.
Crabbe's ankle injury was confirmed after he underwent x-rays.
Coach Kenny Atkinson, who said there is no timetable for Crabbe's return, called the injury "a setback" and said "we'll do the best we can showing him stuff, but it's not the same."
In 79 games with Portland last season, Crabbe averaged 10.7 points, 2.9 rebounds, and 1.2 assists. He spent the first four seasons of his career with Portland before he was traded to Brooklyn over the summer in exchange for F Andrew Nicholson.