The league announced the suspensions Friday without disclosing details of the violations.
The 31-year-old Ellis averaged 8.5 points a game for Indiana last season. Pacers president of basketball operations Kevin Pritchard said the suspension was a "very serious matter" and would be dealt with.
The 26-year-old Bullock averaged 4.5 points in 2016-17. A spokesman for the Pistons said the organization was aware of the suspension but declined further comment.