Starters
Horford
Tatum
Baynes
Irving
Brown
2nd unit
Theis (His minutes would be squeezed the most)
Morris
Monroe
Smart
Rozier
I think the plan is to have Monroe come off the bench and feature him vs second units. I do think it's not too effective, from a minutes perspective, to have him play with the starters where his usage rate would suffer. Instead let's keep those minutes optimal by having the better defensive player (Baynes) continue to start and do some of the dirty work (defense, screens, hard fouls, rebounding, etc.) the first unit needs.
It will be interesting to see how the rotation looks going forward with a possible Hayward return and/or a Tyreke trade. As for the latter, these are the schedule dates for when the post-season rounds are set to begin, with the days to that date from today. Obviously the days are crucial as it gives an idea of the time Hayward has to return.
1st round - April 14 (70 days away)
ECSF - April 30 (86 days away)
ECF - May 15 (101 days away)
NBA Finals - 31 (117 days away)