The San Francisco Giants need Buster Posey to be healthy and productive if they want to contend in the NL West.
There is a nuance to that statement. It is not just a matter of Posey needing to stay on the field. He needs to be healthy enough to produce in the middle of the lineup. In the second half of 2013 Posey was so worn down that he could only manage a .244/.333/.310 in the second half slash line.
They do not need Posey to hit for a ton of power, but he definitely needs to slug better than .310. Early in Spring Training, Posey is showing good signs, as seen with this home run on Tuesday (video from MLB.com):
Posey showed up to camp bulkier, determined to hold up over the course of the season. Whether or not that plan works will say a lot about what happens for the Giants and the rest of the National League West.