In recent days, the SF Giants have DFA'd two outfielders in Joey Wiemer and Wade Meckler. They also recently moved on from Marco Luciano and may not be done making cuts to their outfield ranks.
These moves may suggest that the Giants are planning to make some sort of upgrade to the outfield, or maybe it is just a realization that they have too many outfielders without any minor league options on the 40-man roster and it is a natural thinning of the herd.
SF Giants may move on from even more outfielders after recent moves
Either way, there is not going to be enough room on the team for all of their outfielders to make it onto next year's Opening Day roster.