Is it time for the Giants to consider the harsh truth of a rebuild?Larry Baer has a clear answer: only if Buster Posey says so.The team president and chief executive officer stepped in for Posey on KNBR on Wednesday morning — the second-year president of baseball operations originally was scheduled as the guest — and quickly found himself fielding the question Giants fans have been asking all season. If Posey recommended blowing it up and rebuilding around 21-year-old first baseman Bryce Eldridge, would ownership go along with it?Baer did not hesitate.“I think we will take Buster’s recommendation, because we have faith in Buster,” Baer said. “So if that was the recommendation, I don’t think there’d be any pushback — if that’s the way to make this franchise the best it can be over time. But, by the way, that’s not what he’s saying. I think what he’s saying is, ‘No, let’s play the next month and see where we are.’”For now, the Giants are playing it out. But Baer made it clear that no option is off the table, and that ownership’s loyalty runs entirely through Posey.The...