Kornet only played 2 min and Brissett 2 min vs. MIA last game. That would be 4 minutes for Tillman if he takes these minutes.
We are very solid through 8, with 6,7,8 being Horford (1,188 min), Hauser (1,119 min), Pritchard (1,091 min). Then there is a big drop off to Kornet (548 min) and Brissett (371 min) for the 9th and 10th most minutes. Queta is 11th at 270 min. He would probably have more if he was in the mix right from the start.
So yes, top 8 is set and then Kornet, Tillman, and Brissett (and maybe Queta) will all be options for a few remaining minutes.