Getting Hayward back ... Joining the team on road trips means he expects to be ready, and accordingly I at this point expect him to be back.
If Hayward starts playing in March - and it would be a great help to get him game reps before the playoffs start - we'll likely see more small lineups. Unless he plays a classic sixth man role - likely enough when he first returns - the starting lineup would predictably be:
Irving/Brown/Hayward/Tatum/Horford
... in other words, the Celtics' second most used lineup this year, except with Hayward in for Smart. Smart, in that lineup, gives Irving a break so that he can play off the ball; Gordon would also give Irving a break, though in a different way.
That lineup (with Smart, that is) is neutral for turnovers, and negative for rebounding. Gordon has never been any great shakes on either board, but he was outstanding last season at taking care of the ball, even with a really high usage rate. Smart has been really bad at turning it over this season, on the other hand.
Also worthy of note is how the mere addition of Hayward playing starter's minutes dramatically impacts the depth chart. What happens to Smart, Morris, Theis, Ojeleye, and Monroe?