Bryant collided with cornerback Orlando Scandrick near the end of Friday's practice session and required the assistance of trainers to leave the field.
An examination revealed the sprain and club officials said Bryant would spend the next two weeks in a walking boot. He is expected to miss the entire exhibition season.
Bryant was selected with the 24th pick in the draft. He created a stir in training camp when he declined to take part in the rookie tradition of carrying the shoulder pads of a veteran player -- in this case his chief competition for a starting position, Roy Williams.