Jabari Parker is owed $2,283,034 for the 2021-22 season, but unlike all the other Celtics under contract, his deal is a non-guaranteed one. Based on the fact that the Celtics never talk about him and there has been no news about his Celtics future, it would be safe to assume that the odds are more likely that he won't be on Boston's roster come opening night.
Opening night is when half of his contract becomes guaranteed. Today $100,000 of his contract became guaranteed, so there still is some hope. For Brad Stevens and the Celtics there wasn't much of a reason to waive Jabari prior to today.