If the Giants intend on contending, than they need EVERYTHING except a C, 2B, and SS. So Olney saying the Giants “need” a SP is only accurate in that regard, but would be equally accurate for almost ever single FA.
Fangraphs current depth chart projections have the Giants at 81-81 next year, a few games back of Arizona for the 2nd WC. Giants infield looks pretty good with Belt and Longoria projecting to be above average players, though the Giants OF looks very suspect. The rotation (or at least the top 3) should be pretty good.