Lou Williams has not yet been cleared to return to training following a knee injury sustained in January.
The Atlanta Hawks guard tore his cruciate ligament in a game against the Brooklyn Nets last season but was expected to be fit for the new season.
However, his place in the team for the new campaign has been thrown into doubt as doctors have not been able to allow him to begin training.
Atlanta's pre-season training begins at the start of October but Williams is expected to miss some of the camp due to the new setback, according to Atlanta Journal-Constitution.
Williams joined Atlanta from the Philadelphia 76ers in 2012.