James Harden was going up for a layup. Paul George was going up to contest the shot. When they came down, George had broken his leg and Harden had to look on, petrified and perplexed by what transpired. “That was tough,” said Harden, who struggled to watch as George agonized near the basket stanchion. The unfortunate, seemingly innocuous sequence in a nationally-televised Team USA scrimmage earlier this month set off a short-lived debate about NBA stars participating in international basketball, forced George into a lengthy recovery process and inadvertently thrust Harden into a role that the Houston Rockets all-star guard hadn’t foreseen when USA Basketball first announced its 28-man tryout pool for the FIBA World Cup last January. Harden’s responsibilities increased once more when Kevin Durant, his close friend and former Oklahoma City Thunder teammate, backed out of his commitment, citing fatigue and not the injury to George as the reason. That left the lefty Harden as the only first-team all-NBA player remaining on the squad. The earlier withdrawals of Kevin Love and Russell Westbrook also meant that Harden and Anthony Davis were the only holdovers from the 2012 London Olympics team.