Oakland has been eliminated from first place.

To show that Oakland is eliminated from first place, we start with the current standings:
            Team	W	L	GL	PCT	GB
         Houston	88	73	1	0.547	0.0
         Seattle	85	77	0	0.525	3.5
           Texas	78	84	0	0.481	10.5
         Oakland	69	93	0	0.426	19.5
     Los Angeles	63	99	0	0.389	25.5
           Total	383	426	1

Oakland can finish the season with at most 69 + 0 = 69 wins and will finish the season behind the following teams:
Houston has already won 88 games.
Seattle has already won 85 games.
Texas has already won 78 games.
# Oakland Athletics' magic number
# Oakland's magic number
# Athletics' magic number
# MLB Playoff Race