"I am human," he said, via Stephen Watson of WISN 12 News. "I have a right to be frustrated. I've waited two years for this."
Parker has played a total of 25 minutes in each of Milwaukee's first two playoff games against the Celtics. He has scored just two points on 1-of-7 shooting with six rebounds.
Gery Woelfel of 105.7 The Fan said last month that the Bucks were "very close" to dealing Parker at the trade deadline in February, and there was little chance the 23-year-old would be with the team next season.
After tearing his ACL in February 2017, Parker returned to the Bucks on Feb. 2. He averaged 24 minutes per game with 12.6 points and 4.9 rebounds per contest.
The Bucks return home Friday to host the Celtics for Game 3 of their Eastern Conference playoff series.