Jackson (undisclosed) will not participate in the Pacers' 5-on-5 scrimmage Sunday, Tony East of SI.com reports.
Jackson was a limited participant in practice Friday, and he remains a question mark ahead of the season due to an undisclosed injury. The 22-year-old is expected to serve as the backup center to Myles Turner, but an extended absence could open the door for James Wiseman (groin) to receive more minutes.