Boston has been eliminated from first place.

To show that Boston is eliminated from first place, we start with the current standings:
            Team	W	L	GL	PCT	GB
        New York	94	68	0	0.580	0.0
         Toronto	94	68	0	0.580	0.0
          Boston	89	73	0	0.549	5.0
       Tampa Bay	77	85	0	0.475	17.0
       Baltimore	75	87	0	0.463	19.0
           Total	429	381	0

Boston can finish the season with at most 89 + 0 = 89 wins and will finish the season behind the following teams:
New York has already won 94 games.
Toronto has already won 94 games.
# Boston Red Sox' magic number
# Boston's magic number
# Red Sox' magic number
# MLB Playoff Race