It looks like MIL is playing everyone except MarJon Beauchamp. I guess they need this game more than BOS does. BOS is still favored by 3.5 pts, I am not sure if this line reflects the final injury report. MIL wasn't able to beat TOR or MEM or WAS in recent games, so maybe BOS without Porzingis and Horford can beat them (MIL didn't have Giannis and/or Lillard in those games).
It may not seem like it but loses are not good for Mojo or whatever you want to call it. You want to go into the playoffs with as much good Mojo as possible. I will trust that Porzingis and Horford really do need rest. We are still favored so it is still a winnable game.