Arizona has been eliminated from first place.

To show that Arizona is eliminated from first place, we start with the current standings:
            Team	W	L	GL	PCT	GB
       LADodgers	100	62	0	0.617	0.0
        SanDiego	91	71	0	0.562	9.0
         Arizona	86	76	0	0.531	14.0
    SanFrancisco	65	97	0	0.401	35.0
        Colorado	58	104	0	0.358	42.0
           Total	400	410	0

Arizona can finish the season with at most 86 + 0 = 86 wins and will finish the season behind the following teams:
LADodgers has already won 100 games.
SanDiego has already won 91 games.
# Arizona Diamondbacks' magic number
# Arizona's magic number
# Diamondbacks' magic number
# MLB Playoff Race