Atlanta is eliminated from first place.

To show that Atlanta is eliminated from first place, we start with the current conference standings:
            Team	W	L	GL	PCT	GB
       Cleveland	64	18	0	0.780	0.0
          Boston	61	21	0	0.744	3.0
        New York	51	31	0	0.622	13.0
         Indiana	50	32	0	0.610	14.0
       Milwaukee	48	34	0	0.585	16.0
         Detroit	44	38	0	0.537	20.0
         Orlando	41	41	0	0.500	23.0
         Atlanta	40	42	0	0.488	24.0
         Chicago	39	43	0	0.476	25.0
           Miami	37	45	0	0.451	27.0
         Toronto	30	52	0	0.366	34.0
        Brooklyn	26	56	0	0.317	38.0
    Philadelphia	24	58	0	0.293	40.0
       Charlotte	19	63	0	0.232	45.0
      Washington	18	64	0	0.220	46.0
           Total	592	638	0

Atlanta can finish the season with at most 40 + 0 = 40 wins and will finish the season behind the following teams:
Cleveland has already won 64 games.
Boston has already won 61 games.
New York has already won 51 games.
Indiana has already won 50 games.
Milwaukee has already won 48 games.
Detroit has already won 44 games.
Orlando has already won 41 games.