An MRI on Grffin's knee showed no structural damage, and coach Doc Rivers said there's no timetable for his return.
"It's nothing bad," Rivers said. "But he tweaked it."
Griffin was injured on the final play of the scrimmage when he attempted a dunk over Lou Amundson.
"Every time I've hurt my knee the previous time, it was always like when I planted, when I was going up and not coming down," Griffin said before practice Friday, according to the Los Angeles Times. "So, just that alone was kind of scary to me. But as soon as we got the news, it's one of those things that you can deal with pain if you know what the pain is."
Rivers said Barnes is day to day, and Redick could be out for a week to 10 days.