Rozier is nothing special, just another shoot-first combo guard prone to heroballing. Most replaceable type of player in the league. He never should have been on the team this year in the first place, since putting up numbers in the playoffs and then bumped back down to Kyrie's backup pissed him off and stunted his development.
Smart can start and the Celtics can sign literally anyone capable of staying in front of their man to be the backup.