Beyond the rampant skepticism about the severity of his latest hamstring injury, on top of the ever-present questions about his substandard conditioning and how much it contributed to his unending hamstring troubles as a Net, Harden has been a brooding presence for months. League sources say there were times before Durant’s injury that the two stars, for reasons unclear, were hardly communicating — followed by the chaos of the past few Durant-less weeks when Harden stopped connecting with anyone to passive-aggressively convey he no longer wanted to be there.