San Francisco has been eliminated from first place.

To show that San Francisco is eliminated from first place, we start with the current standings:
            Team	W	L	GL	PCT	GB
     Los Angeles	92	70	0	0.568	0.0
       San Diego	90	72	0	0.556	2.0
   San Francisco	81	81	0	0.500	11.0
         Arizona	80	82	0	0.494	12.0
        Colorado	43	119	0	0.265	49.0
           Total	386	424	0

San Francisco can finish the season with at most 81 + 0 = 81 wins and will finish the season behind the following teams:
Los Angeles has already won 92 games.
San Diego has already won 90 games.
# San Francisco Giants' magic number
# San Francisco's magic number
# Giants' magic number
# MLB Playoff Race